Mikro tik advanced training

MikroTik RouterOS
Training
Advanced Class
Johannesburg South Africa
April 14 – 17, 2009

Schedule

● 09:00 – 10:30 Morning Session I
● 11:00 – 12:30 Morning Session II
● 12:30 – 13:30 Lunch
● 13:30 – 15:00 Afternoon Session I
● 15:30 – 17:00 Afternoon Session II

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Instructor
● Christopher Sutherland
– Support and Training engineer for Miro distribution

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Housekeeping
● Course materials
● Routers, cables
● Break times and lunch
● Restrooms and smoking area locations

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Course Objective
● Provide knowledge about advanced features of
MikroTik RouterOS and hands-on training for
configuring, maintaining and troubleshooting
networks built using RouterOS software and
RouterBoard hardware
● Upon completion of the course you will be able
to plan and implement advanced network
configurations using RouterOS

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About MikroTik
● Mission Statement
– MikroTik is a router software and hardware
manufacturer, that offers user friendly carrier-class
routing and network management solutions. Their
products are used by ISPs, individual users and
companies for building data network infrastructures.
● Their goal is to make existing Internet
technologies faster, more powerful and more
affordable to wider range of users

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MikroTik's History
● Active in WISP solutions since 1995
● Incorporated in 1996
● Wireless ISP Projects around the World
● Since 1997 Development of own Software for
Intel (PC) based routing solutions
● Since 2002 Development of own Hardware
● 2006: 60 employees

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Where is MikroTik?
● They are on the World Wide Web at
www.mikrotik.com
● Located in Riga, Latvia, Eastern Europe, EU

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Introduce Yourself
● Please introduce yourself to the class:
– Your Name
– Your Company
– Previous knowledge about RouterOS
– Previous knowledge about data networking
– What do you expect from this course?

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Class Setup
● Please remember your number XY in the class
● My number is:__________

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Get Connected!
● Connect to your router and:
– Set System Identity to your Number_Name
– Set Radio Name for wireless as Number_Name
– Use SSID “mainAP” and mode=station
– Add IP address 10.1.1.___/24 for wireless
– Default gateway is 10.1.1.254
– DNS Server is 10.1.1.254
– Use masquerading to hide your private LAN
– Test, if you can browse! Back up the configuration!
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Create a Backup

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Security and Routing

Bridge Features, Firewall, Policy Routing,
ECMP Routing, Dynamic Routing

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Bridge
● Ethernet-like networks can be connected
together using OSI Layer 2 bridges
● The bridge feature allows interconnection of
hosts connected to separate LANs as if they
were attached to a single LAN segment
● Bridges extend the broadcast domain and
increase the network traffic on bridged LAN

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Bridge Configuration
● Bridge is a virtual interface in RouterOS
● Several bridges can be created
– /interface bridge add name=bridge1
● Interfaces are assigned as ports to a bridge
– /interface bridge port add interface=ether1
bridge=bridge1
– /interface bridge port add interface=ether2
bridge=bridge1

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Creating a Bridge

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Assigning Ports to the Bridge

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Spanning Tree Protocol
● The Spanning Tree Protocol (STP)
– is defined by IEEE Standard 802.1D
– provides a loop free topology for any bridged LAN
– finds a spanning tree within the mesh network and
disables the links not part of that tree

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STP in Action

A
B

D
C
Root
Bridge
E F

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Spanning Tree
Root
Bridge
C

E B A

F D

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Rapid Spanning Tree Protocol
● Rapid Spanning Tree Protocol (RSTP)
– is an evolution of the STP
– provides faster spanning tree convergence after a
topology change than STP
● rstp-bridge-test package is required for the
RSTP feature to be available in RouterOS

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Routed Networks vs Bridging
● Routers do not forward broadcast frames
● Communication loops and their resultant
broadcast storms are no longer a design issue
in routed networks
● Redundant media and meshed topologies can
offer traffic load sharing and more robust fault
tolerance than bridged network topologies

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IP Firewall Filters
● Firewalls are used as a means of preventing or
minimizing the security risks inherent in
connecting to other networks
● IP firewall filters
– are a tool to apply traffic policies based on flow
properties
– allow stateful packet inspection
– separately manage traffic flowing to, from and
through the router

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Stateful Inspection
● Stateful inspection tracks each connection
traversing all interfaces of the firewall and
makes sure they are valid
● The examination may include
– the header information about its source and
destination
– the contents of the packet up through the
application layer in order to determine more about
the packet

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Mikrotik RouterOS Services

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Mikrotik RouterOS Services (cont.)

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Connection Tracking
● Connection Tracking (CONNTRACK) is a system that
gathers and stores information about active
connections
● A connection is defined as a bidirectional data
exchange
● CONNTRACK information is not limited to TCP
connections
● Firewall facilities can use CONNTRACK information
to classify packets
● CONNTRACK is necessary for Network Address
Translation (NAT) and Mangle

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Connection Tracking Table

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Condition: Connection State
● A status assigned to each packet:
– Invalid – packet does not belong to any of the
known connections
– New – packet opens a new connection
– Established – packet belongs to already known
connection
– Related – packet creates a new connection that is
in some way related to an already known
connection
● Connection state ≠ TCP state

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Filter Rule
● Firewall filter rule is an IF-THEN statement
IF <condition(s)> THEN <action>
● Packet traverses through rules in a definite
order, from top to bottom
● If a packet matches all conditions of a rule, then
the specified action is performed on it.
Otherwise, the next rule is evaluated

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Firewall Filter Structure
● Firewall filter rules are organized in chains
● Chains are sets of rules grouped together
● There are three built-in chains:
– input – processes packets addressed to the router
– output – processes packets originated by the
router
– forward – processes traffic flowing through the
router

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Packet Flow Diagram
● Refer to the Packet Flow Diagram whenever
you need to find out how packets are processed
by the router

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User-Defined Chains
● Help to reduce the average number of lookup
steps needed to process a packet, thus
improving the performance
● Frequently used to optimize firewall structure
and make it more readable and manageable

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User-Defined Chains (cont.)
● The traffic can reach user-defined chains only
from one of the default chains with the help of
the rules with action=jump
● The chain is created as soon as a rule for the
chain is added

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Monitoring the Firewall
● Each rule has counters of packets and bytes that
passed through it
● Rules can be moved to arrange them in the desired
processing order
● Make rules with action=log to see the kinds of
packets that are processed
● Use action=passthrough to add simple counter rules
● Use connection tracking table to see current
connections

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Firewall Strategies
● Accept everything ● Drop everything
except 'bad' traffic except 'good' traffic

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Firewall Rule Actions
● The most basic firewall rule actions are
– accept – accept the packet and stop evaluating
other rules
– drop – silently discard the packet
– reject - drop the packet and send ICMP reject
message
– jump – jump to the chain specified by the jump-
target parameter value

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More Firewall Rule Actions
● More firewall rule actions are
– jump – jump to the chain specified by the jump-
target parameter value
– return – return to the previous chain, from where
the jump took place

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Firewall Filter Rule Sequence
● Since the majority of the packets is most likely
going to be packets belonging to established
connections, it is wise to put a rule accepting
them in the beginning (top) of the firewall filter
● In such a way, the firewall filters are processed
more efficiently
● Further rules may be those dealing with packets
establishing new connections

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Firewall Rule Lab
● Add following rules to the “input” chain of the
firewall filter:
– Accept all packets with “Connection State”
”established”
– Accept all packets with “Connection State”
“related”
– Drop all packets with “Connection State” “invalid”
● Monitor the firewall rule counters

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Port Scan Detection (PSD)
● PSD detects connection attempts to different
ports appearing in quick succession
● High (privileged) ports are from 0 to 1023

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PSD Example
● A rule to detect and
drop attempts to scan
open ports of the
router

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Limit Matcher
● A rule with Limit will match until a given rate is
reached
● Burst specifies initial number of packets to
match: this number gets recharged by one
every time the rate is not reached

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Limit Matcher Example
● Reduce the amount
of log messages

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Firewall Filter Limit Lab

● Limit the rules allowing ICMP packets to 5
packets per second (block Ping Flood attacks)
● Modify the rule to instantly allow first 5 packets
● Add a rule to log HTTP traffic going trough the
router at a rate of 200 packets per hour

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Connection Limit
● Connection limit limits the packet per second
(pps) rate on a per destination IP or per
destination port base
● As opposed to the limit match, every destination
IP address / destination port has it's own limit

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Connection Limit Lab
● Limit the number of
active HTTP
connections to 5 per
single IP address
● Think about the
various effects of the
rule above

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SYN Flood

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Dealing with DoS Attacks
● Limit the number of active connections
● Optimize processing workflow
● Enable TCP SYN cookies
● Use rules with action=tarpit

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TCP SYN Cookie
● SYN cookie protects against TCP SYN flooding
● Instead of allocating a record, it sends a SYN-
ACK with a carefully constructed sequence
number generated as a hash of the clients IP
address, port number, and other information

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Enable TCP SYN Cookies

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Some Observations about Attacks
● Those, who attacked once, will probably attack
in the future
● Most attacks are automated (at least partially)
● Attackers seek a “positive” outcome

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More Firewall Actions
● tarpit – drop the packet and reply with
SYN,ACK to the inbound TCP SYN packet
● add-dst-to-address-list – add packet’s
destination address to the specified address list
● add-src-to-address-list – add packet’s source
address to the specified address list

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Address Lists
● A convenient way to group prefixes
● Dynamic or static

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Address List Lab
● Limit the number of
active connections to
5 per single IP
address
● Modify the rule and
change action to add
source address to
address list

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Address List Lab (cont.)
● Add new rule to either drop or tarpit
connections from addresses in BlackList
● Place this rule on top of the input chain

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Layer 7 Protocols
● New to v3 is a Layer 7 Protocol system
● This can be used throughout the firewall system
● Refer to the Wiki for common Layer 7 protocols
● http://wiki.mikrotik.com/wiki/L7

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Last Issue
● Note, that IP Firewall filters do not filter Level 2
communications, e.g., MAC-Telnet and MAC-
WinBox
– Turn off MAC-Telnet at least on the public interface
to ensure higher security.
– Turn off MAC-WinBox at least on the public
interface to ensure higher security
● RouterOS has a separate Layer 2 firewall

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Disable MAC-Server Lab
● Disable MAC-
WinBox on all
interfaces except
local
● Disable MAC-
Telnet an all
interfaces except
local

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Firewall NAT in General
● Network Address Translation (NAT) is a
networking technique for replacing IP protocol
addresses and ports of packets as they pass
through the router
● There are two types of NAT:
– Source NAT for replacing the source IP address
and/or port
– Destination NAT for replacing the destination IP
address and/or port

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Firewall NAT Structure
● NAT rule is an IF-THEN statement
– IF <condition(s)> THEN <action>

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NAT Chains
● NAT rules are organized in chains
● There are two built-in chains:
– dstnat - used for changing destination address and
ports. (actions src-nat and masquerade can not be
used in this chain)
– srcnat - used for changing source address and
ports. (actions dst-nat and redirect can not be used
in this chain)
● New user-defined chains can be added, as
necessary
© MikroTik 2007 65

“Known” NAT Actions (1/2)
● accept - the packet is accepted by the router
● jump – jump to the chain specified by the jump-
target argument value
● return – return to the previous chain, from
where the jump took place
● log – add a record to log file when all conditions
of a rule are satisfied
● passthrough - ignore this rule and go on to the
next one
© MikroTik 2007 66

“Known” NAT Actions (2/2)

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“New” NAT Actions
● There are 6 new actions in the NAT:
– “src-nat” and “masquarade” change source
address and/or port of IP packet
– “dst-nat” and “redirect” change destination
address and/or port of IP packet
– “netmap” creates a static 1:1 mapping of one set
of IP addresses to another one
– “same” gives a particular client the same
source/destination IP address from supplied range
for each connection
© MikroTik 2007 68

Masquerade and Source NAT
● Both “masquerade” and “src-nat” change the
source IP address and/or port of an IP packet
● For the new source address,
– “masquerade” uses the IP address of the router by
default
– “src-nat” uses the specified “to-address”

© MikroTik 2007 69

Source NAT Applications
● A typical application of masquerading and
source NAT is hiding a private network behind
one or more external addresses to
– enhance network security, and
– conserve IP address space

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SRC-NAT Lab
● Hide your LAN 192.168.____.0/24 behind
router's IP address 10.1.1.____
● Make your workstation to be hidden behind a
“public” IP address 172.16.1.____, but the rest
of the LAN stays hidden behind the router's IP
address

© MikroTik 2007 71

Redirect and Destination NAT
● Both “redirect” and “dst-nat” change the
destination IP address and/or port of an IP
packet
● For the new destination address,
– “redirect” uses the IP address of the router by
default, i.e., it “grabs” the packet and sends it to the
router itself
– “dst-nat” uses the specified “to-address”

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Destination NAT Applications
● Action dst-nat is typically used for accessing
services on a private network from public
addresses via a public address
● Action redirect is mostly used for proxying
network requests (for example, providing
transparent HTTP, DNS or other proxy
services)

© MikroTik 2007 73

Destination NAT Lab #1
● Add a dst-nat rule to redirect TCP port 2323
connection requests to router's TCP port 23
● From your workstation, try establishing a telnet
connection to port 2323 of the main router
10.1.1.254 or of any other host
– Use C:>telnet 10.1.1.254 2323
– Check if the counters of the NAT rule change
– Check if you can get the login prompt of your own
router

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● Configure destination NAT to send all client's
HTTP requests to a specific server, say, to the
access point's ip address 10.1.1.254
● Check how the rule is working
– Try to access yahoo.com, google.com, etc.
– Are you getting only AP's welcome page wherever
you go?
– Monitore the counters

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● Make your router accessible by HTTP at TCP
port 81
– Check if you can access your router at
http://192.168.___.254:81

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Firewall Mangle
● The mangle facility allows to mark IP packets
with special marks
● These marks are used to identify the packets by
– other mangle rules, firewall filter rules
– simple queues, queue trees
– policy routing
● In addition, the mangle facility is used to modify
some fields in the IP header, like TOS and TTL
fields

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Mangle Configuration

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Mangle Structure
● Mangle rule is an IF-THEN statement
– IF <condition(s)> THEN <action>

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Mangle Conditions and Action

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Mangle Chains
● Mangle rules are organized in chains
● There are five built-in chains:
– Prerouting- is processed before Global-In queue
– Postrouting – is processed before Global-Out
queue
– Input – is processed before Input filter
– Output – is processed before Output filter
– Forward – is processed before Forward filter
● New user-defined chains can be added, as
necessary
© MikroTik 2007 81

“Known” Mangle Actions (1/2)
● accept – accept the packet and stop
processing other rules in the chain
● jump – jump to the chain specified by the value
of the jump-target argument
● return – return to the previous chain, from
where the jump took place
● log - log packet matches
● passthrough - ignore this rule and go on to the
next one

© MikroTik 2007 82

“Known” Mangle Actions (2/2)

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“New” Mangle Actions
● There are 7 more actions in the mangle:
– mark-connection – mark connection
– mark-packet – mark entire flow (all packets)
– mark-routing - mark packets for policy routing
– change MSS - change maximum segment size of
the packet
– change TOS - change type of service field value
– change TTL - change time to live field value
– strip IPv4 options

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A: Marking Connections
● Mark connection to identify all packets
belonging to a certain connection, e.g., http or
ftp traffic
– Set connection mark to be used in other mangle
rules
– Specify “passthrough=yes” so the processing of
mangle rules is continued
● Mark packets based on the connection mark
– Set packet mark to be used in queue trees, or
– Set routing mark to be used in routing
© MikroTik 2007 85

B: Marking Packets
● Packets can be marked without using the
connection mark, for example, based on
protocol and port.
● There might be problems when identifying, for
example, web proxy requests and responses:
– TCP destination port 8080
– TCP source port 8080 can match source port of a
client's request to a server

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Mangle Lab
● Mark all HTTP connections
● Mark all packets belong to these connections
● Add the simple queue with HTTP limitation
● Check the limitations!

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Dynamic Address Lists
● Use the mangle action “add src to address list”
or “add dst to address list” to dynamically create
address lists of certain hosts
● Once added to the list, the addresses are kept
there for the timeout period.
● Some possible uses of dynamic address lists:
– Blacklisting attackers and intruders and filtering
them out based on the address list

© MikroTik 2007 88

Dynamic Address List Lab
● Try creating dynamic address list of all source
addresses for HTTP requests going to or
through the router
– Go to the “IP” > “Firewall” “Mangle” tab
– Add a mangle rule to the “prerouting” chain for TCP
port 80 requests
– Specify “Action”, “Address List”, and “Timeout”
● Monitor the address list and see for how long
time period the addresses stay there

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Dynamic Address List Lab (cont.)
● Create another mangle rule that adds all
destination addresses of HTTP connections
through the router to another address list

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P2P Traffic Identification Lab
● Add a mangle rule to identify and mark all p2p
connections
– Select the “forward” chain and set “P2P” to “all-p2p”
– Use “Action” “mark connection” and specify a “New
Connection Mark”
– Enable “Passthrough”
● See “Statistics” for bytes and packets
– You may need to force the p2p connections to be
re-established in order to identify them

© MikroTik 2007 91

Bridge Firewall
● The bridge firewall implements packet filtering
and thereby provides security functions that are
used to manage data flow to, from and through
bridge
● Elements of bridge firewall are:
– Bridge Filter
– Bridge Network Address Translation (NAT)
– Bridge Route

© MikroTik 2007 92

Bridge Filter
● Bridge filter has three predefined chains, input,
forward, and output
● Bridging filters are always applied before IP
filters/NAT of the built-in chain of the same
name, except for the output which is executed
after IP Firewall Output
● Example application is filtering broadcast traffic

© MikroTik 2007 93

Bridge NAT
● Bridge network address translation (NAT)
– provides ways for changing source/destination MAC
addresses of the packets traversing a bridge
– has two built-in chains
● src-nat
● dst-nat
● Bridge NAT can be used for ARP

© MikroTik 2007 94

Bridge Route
● Bridge Route
– makes bridge a brouter - router that performs
routing on some of the packets, and bridging - on
others
– has one predefined chain, brouting, which is
traversed right after a packet enters an enslaved
interface before "Bridging Decision"
● For example, IP can be routed, and everything
else bridged

© MikroTik 2007 95

VRRP
● Virtual Router Redundancy Protocol
● A number of VRRP routers to form a virtual
router
● Each VRRP node can have following states:
– MASTER state (there can be only one master node
in virtual router)
– BACKUP state – if MASTER node goes down,
election process happens and BACKUP node
becomes master based on nodes priority.

© MikroTik 2007 96

VRRP Fail-Over Example

ISP 1 ISP 2

GW 1 GW 2

192.168.0.0/24

© MikroTik 2007 97

VRRP Properties
● Interface - which interface to use for VRRP.
● vrid – Virtual Router Identifier. Available range
is from 1-255 (decimal)
●
Priority - Priority value to be used by this VRRP
router in Master election. Available range is
from 1-254 (decimal):
– 255 is reserved to Router that owns IP
– 0 is reserved for Master router to indicate that it is
releasing responsibility

© MikroTik 2007 98

VRRP Properties (cont.)
● Interval – defines how often master sends
advertisement packets.
● Preemption-mode – whether master node
always has the priority

© MikroTik 2007 99

Adding VRRP Interface

© MikroTik 2007 100

Adding VRRP Interface (cont.)


VRRP Security
● VRRP exchange Authentication:
– none – use only in low security risk networks (e.g.,
two VRRP nodes on LAN).
– simple – uses clear text password. Protects against
accidental misconfiguration of routers on a LAN.
– ah – IP Authentication Header:
● Provides strong protection against configuration errors,
replay attacks, and packet corruption/modification
● RECOMMENDED when there is limited control over the
administration of nodes on a LAN


VRRP Example
ISP 1 ISP 2

ip: 10.0.0.1/24 ip: 10.0.1.1/24
gw:10.0.0.254 gw:10.0.1.254

VRRP VRRP
main backup

ip: 192.168.1.2/24 ip: 192.168.1.3/24
VRRP
ip: 192.168.1.1/24

Client
IP: 192.168.1.254/24
GW:192.168.1.1

VRRP Example Part I

● Set up MASTER router:
– add VRRP interface
/interface vrrp add interface=local priority=255
vrid=1
– add local interface ip address
/ip address add address=192.168.1.2/24
interface=local
– add VRRP interface ip address
interfce=vrrp1


VRRP Example Part II

● Set up BACKUP router:
– add VRRP interface
/interface vrrp add interface=local priority=100
vrid=1
– add local interface ip address
interface=local
– add VRRP interface ip address
interfce=vrrp1


VRRP Example Part III
● Set up client router:
– bridge both incoming ethernet ports
/interface bridge add ;
/interface bridge port add bridge=bridge1
interface=ether1 ;
/interface bridge port add bridge=bridge1
interface=ether2;
– add clients ip address and default gateway
interface=bridge1
/ip route add gateway=192.168.1.1


VRRP Example Part IV

● Try to ping gateway from client
● unplug cable connected to MASTER router and
see how it works
● after few seconds backup router becomes
master


Static Routing
● Predictable
● No overhead
● Easy to configure on a small network


ECMP Routing
● The Equal Cost Multipath (ECMP) Routing
mechanism enables packet routing along
multiple paths with equal cost and ensures load
balancing
● A new gateway is chosen for each new source/
destination IP pair


Creating ECMP Routes
● The ECMP routes can be created by
– routing protocols (RIP or OSPF)
– adding a static route with multiple gateways,
separated by a comma (e.g., /ip route add
gateway=192.168.0.1,192.168.1.1)


Policy Based Routing
● Policy based routing is a routing approach
where the next hop (gateway) for a packet is
chosen, based on a policy, which is configured
by the network administrator
● Example policies can be based on:
– protocols (HTTP vs FTP)
– interfaces (incoming/outgoing)
– addresses (source or destination)
– traffic type (p2p and “normal” traffic)


Creating Policy Based Routing
● In RouterOS, the procedure of creating policy
based routing is as follows:
– mark the desired packets with a routing-mark
– choose a gateway for the marked packets


Dynamic Routing
● Scalability
● Adaptability
● The network can adjust to failures


BGP Overview
AS 200
● inter-autonomous system AS 100
routing protocol
● allows to apply complex
policies AS 300

● uses TCP port 179 as its transport


Autonomous System
● a connected group of one or more IP prefixes
run by one or more network operators which
has a SINGLE and CLEARLY DEFINED routing
policy.
● AS is identified by its number
– 16 bit value.
– 64512 through 65535 are “private”


iBGP and eBGP
● BGP is self-constrained protocol (i.e. works
both between ASes and within a single AS)


Local BGP Configuration

● Modify default BGP
instance
● Specify AS number
● Optionally specify
router ID (the highest
IP address will be
chosen automatically)


First BGP Session

● Specify peer's IP
address
● Specify peer's AS
number
● Optionally specify
TCP MD5 key


Route Redistribution

● Global redistribute-*
switches
● Instance filters
● Peer filters


BGP Lab
● Set your router to redistribute connected
networks
● Check what you are actually redistributing
● Verify that your router receives networks via
BGP


Routing Filters
● Allow to deploy arbitrary complex routing
policies

● Out filter for BGP instance

● In and out filters for individual peers


Routing Filters: Matchers


Routing Filters: Actions
● passthrough
● accept
● reject
● jump
● return
● discard


AS_PATH
● the advertised path for a route
● Each EBGP peer prepends their own AS to
each route before sending it out
– The AS-Path, when read left to right is the path the
packet will take from the sender to the receiver, with
the destination AS being the rightmost value
– Since the AS is prepended at the EBGP peer, the
AS-path of a route within an AS won’t contain the
AS itself


NEXT_HOP
● EBGP sets the next hop address to the IP
address of the peer that advertised the prefix
● IBGP sets the next hop address to the IP
address of the peer that advertised the prefix
for routes that originate internally
● IBGP passes the next hop unaltered for
prefixes that are learned with EBGP


COMMUNITIES
● a way to logically classify a prefix for use in policies by
attaching an identifier that is significant within a
network
● communities are represented as two numbers
separated by a “:”, for example “65001:500” or
“65000:750”. Each number can have a range between
0 – 65535. The convention used is to set first number
to the local AS, and the second number to an arbitrary
value that is defined by the networks’ administrative
policy


BGP Weight
● Used to apply local routing policy within a single
router
● Route with numerically greater weight is
preferred


Troubleshooting BGP

● Walk through your
configuration
● Verify connectivity
with peers
● Enable BGP logging


What is OSPF?
OSPF means:
● Open

– Common standard, everybody free to implement or
use it
● Shortest

– Optimal, with less interruptions, best
● Path

– A sequence of links packet needs to pass to reach
destination
● First

– ... to find the above best path


Why do I need one?
● OSPF can be used for:
– switching to a redundant or standby link upon the
failure or abnormal termination of the currently-
active link
– routing topology updates in highly dynamic
network
– ensuring internal AS consistency when using BGP


Before you Begin
● OSPF support in RouterOS is provided via
separate 'routing' package
– Check that the package is installed using '/system
package print' command
– Install the missing package, if required
● Make sure the firewall does not filter out OSPF
communications
– (OSPF neighbors use IP protocol 89 for
communication with each other)


OSPF Settings


Configuration Checklist
● Add networks you want OSPF to be run on to
the '/routing OSPF networks' list
● (optional) Configure general OSPF settings
● Check that OSPF is working
● (optional) Adjust interface parameters, if
necessary
● (optional) Configure redistribution filters


OSPF Networks


OSPF Networks
● Add networks to specify interfaces where you
need OSPF running, and the area
● The network address should include the
address of the interface
/routing ospf network
add network=10.1.0.0/24 area=backbone


OSPF Neighbors
● /routing ospf neighbor print
– Shows OSPF neighbors including router itself


OSPF Neighbor States
● Neighbor state shows status of the OSPF
neighbor:
– Full: link state databases completely synchronized
– 2-Way: bidirectional communication established
– Down, Attempt, Init, Loading, ExStart, Exchange:
not completely running, see the documentation!


OSPF Router ID
● Router ID must be unique within the AS
● Router ID can be left as 0.0.0.0
– Largest IP address assigned to the router will be
used


OSPF Interface Configuration


Redistribution
● Global redistribute- switches

● Routing filters


OSPF Route Redistribution
● Set redistribute connected routes [and static
routes]:
/routing ospf
set redistribute-connected=as-type-1
set redistribute-static=as-type-1
● If you use RIP or BGP as well, you may want
to redistribute routes learned by these
protocols


OSPF Default Route
● Leave ‘Distribute default’ route to ‘never’,
unless it is an ASBR
/routing ospf
set distribute-default=as-type-1


OSPF Routes I
● /ip route print
– DO: a route added by OSPF shows that OSPF is
running on that interface
– Equal cost multipath routes have one destination
address and gateways separated by ‘,’.


OSPF Routes II


OSPF Logs
● OSPF logs show information exchange
between routers:
/system logging add topics=ospf action=memory
● Turn it off after OSPF is set up and running


OSPF Mesh


Configuring Mesh
● Set router to distribute the default route and
redistribute connected routes:
/routing ospf
distribute-default=always-as-type-1
redistribute-connected=as-type-1
● Configure OSPF to run on two local interfaces:
add network 10.0.0.0/8 area=backbone


Configuring Mesh (cont.)
● Set router to redistribute connected routes:
/routing ospf
redistribute-connected=as-type-1
● Configure OSPF to run on all interfaces:
add network 10.0.0.0/8 area=backbone


Areas
● When no OSPF areas are configured, each
router running OSPF has an identical view of
the routing topology of the Autonomous System
(AS)
● OSPF allows collections of contiguous networks
and hosts to be grouped together into areas
● The topology of an area is invisible from the
outside of the area


Area Configuration


OSPF Areas


OSPF Router Types
● Internal routers (inside an area)
● Backbone routers (inside area 0)
● Area border routers (ABR)
– An ABR sits between two or more areas and it
must touch area 0
● Autonomous system boundary routers (ASBR)
– Redistributes routing information between OSPF
and other routing protocols


Area Numbering
● Areas are defined with 32 bit numbers in IP
address format
● 0.0.0.0 reserved for the backbone area
● All areas must connect to area 0.0.0.0
● Configuration
/routing ospf area
print
add name=internal1 area-id=0.0.0.1


Troubleshooting OSPF
● seek to narrow down the source of a problem
by figuring out what is and isn't working until a
single cause is identified
● change only one thing at a time
● make notes as you move forward


Troubleshooting OSPF (cont.)
● Check MikroTik neighbors
/ip neighbor print
● Check OSPF neighbors
/routing ospf neighbor print
● Check routes
/ip route print
● Check logs
/log print


Alternatives to OSPF backup
● Use Netwatch to run scripts that change
routing
● Bridging using EoIP tunnels or WDS
● Hint: when configuring the bridge,
– Turn on Spanning Tree Protocol (STP) to avoid
loops;
– Use port cost argument to set ‘preferred’ path to
be used.


Wireless and Tunnels

Wireless Concepts, Encryption, User Manager,
WDS and Mesh, nStreme Protocol, VLAN,
PPPoE, PPTP, L2TP, IPSec


Wireless Setup Lab
● Upgrade your router to the latest RouterOS
V3.xx
● Set wireless cards “Radio name” option to
“XY_<name>”, where “XY” is your number


Wireless Tools
● RouterOS offers a number of diagnostic tools
for the wireless interface
– Scan for finding access points
– Frequency usage monitor to find free frequency
– Alignment tool to help align antennas
– Sniffer to sniff packets from wireless network
– Snooper to monitor traffic load on each channel


Wireless Scan


Frequency Usage Tool

● Frequency Usage
Monitor looks only for
IEEE 802.11 frames
● Interface is disabled
during the Frequency
usage monitor


Alignment Tool


Wireless Sniffer Tool


Wireless Snooper Tool


Wireless Standards
● IEEE 802.11b
– 2.4ghz-b - 11Mbps
– 2.4ghz-b/g - 11Mbps,
● IEEE 802.11g
– 2.4ghz-b/g - 54Mbps
– 2.4ghz-only-g - 54Mbps
– 2.4ghz-g-turbo - 108Mbps
● IEEE 802.11a
– 5ghz - 54Mbps
– 5ghz-turbo - 108Mbps


Supported Frequencies
● Wireless cards usually support the following
frequencies:
– For all 2.4GHz bands: 2312-2499MHz
– For all 5GHz bands: 4920-6100MHz
● Your country regulations allow only particular
frequency ranges
● Custom frequency license unlocks all
frequencies supported by the wireless hardware


Supported Bands
● All 802.11a and 802.11b/g standard bands
● Variation of IEEE 802.11 with half of the band
– 2Ghz-10MHz and 5Ghz-10MHz
– max rate half of 54 Mbps (27Mbps)
● Variation of IEEE 802.11 with quarter of the
band
– 2Ghz-5MHz and 5Ghz-5MHz
– max rate quarter of 54 Mbps (13.5Mbit)


Channels- 802.11b/g
1 2 3 4 5 6 7 8 9 10 11 2483
2400

● (11) 22 MHz wide channels (US)
● 3 non-overlapping channels
● 3 Access Points can occupy same area
without interfering

Channels- 802.11a
36 40 42 44 48 50 52 56 58 60 64
5210 5250 5290

5150 5180 5200 5220 5240 5260 5280 5300 5320 5350

149 152 153 157 160 161
5760 5800

5735 5745 5765 5785 5805 5815

● (12) 20 MHz wide channels
● (5) 40MHz wide turbo channels

Wireless Interface Mode Settings
● bridge/ap-bridge – AP mode; bridge mode supports only one
client
● station – client which can not be bridged
● station-pseudobridge/station-pseudobridge-clone – client which
can be bridged
● alignment-only – for positioning antennas
● nstreme-dual-slave – card will be used in nstreme-dual interface
● wds-slave – works as ap-bridge mode but adapts to the WDS
peers frequency
● station-wds – client which can be bridged (AP should support
WDS feature)


Wireless AP/Station Lab
● Work in pairs to make AP/Station connection
with your neighbor's router
● Create a AP on the wlan1 interface in 5Ghz
band with SSID “apXY” where XY is your
number
● On wlan2 interface create a station to connect
to your neighbor's AP (you need to know the
neighbor's AP SSID)
● Make a backup from this configuration


Registration Table


Clients Access Management
● default-forwarding – gives ability to disable the
communication between the wireless clients
● default-authentication – enables AP to register
a client even if it is not in access list. In turn for
client it allows to associate with AP not listed in
client's connect list


Wireless Access List
●Individual settings for each client in access list
will override the interface default settings
● Access list entries can be made from the
registration table entries by using action 'Copy to
Access List'
● Access list entries are ordered, just like in
firewall
● Matching by all interfaces “interface=all”
● “Time” - works just like in firewall


Wireless Access list


Wireless Access List


Wireless Access List Lab
● Check if the neighbor's wireless router is
connected to your AP interface (wlan1)
● Disable the default interface settings on wlan1:
default-forwarding, default-authentication
● Make sure that nobody is connected to your AP
● Add access list entry with your neighbor's MAC
address and make sure it connects


Wireless RADIUS Authentication


Wireless Connect List
●Allow or deny clients from connecting to
specific AP by using Connect list
● Connect list entries can be made from the
registration table entries by using action 'Copy to
Connect List'
● Connect list entries are ordered, just like in
firewall
● Used also for WDS links



1 2

3


Wireless Connect List Lab
● On the AP interface (wlan1) enable the 'hide-
ssid' option
● On the Station interface (wlan2) leave the SSID
field empty
● Add connect list entry for wlan2 interface to
connect to your neighbor's AP (you will need
the neighbor's AP MAC address)


Rate Dependency from Signal Level
-60 Signal,
dBm

Link signal
level

Card Receive
Sensitivity

-100
Rates,
6 9 12 18 24 36 48 54 Mbps

Rate Jumping
5% of time
80% of time
54Mbps
15% of time 48Mbps
36Mbps

Recalibration Recalibration

● You can optimize link performance, by avoiding
rate jumps, in this case link will work more
stable at 36Mbps rate


Basic and Supported Rates
● Supported rates –
client data rates
● Basic rates – link
management data
rates

● If router can't send
or receive data at
basic rate – link
goes down


Wireless Encryption


Wireless Encryption Lab
● Create a new security profile with options:
mode=dynamic-keys
authentication-type=wpa2-psk
group/unicast ciphers=aes-ccm
wpa2-key=wireless
● Apply the new profile to wlan1 and check if the
neighbors wireless client connects


Wireless Distribution System
● WDS (Wireless Distribution System) allows
packets to pass from one AP to another, just as
if the APs were ports on a wired Ethernet switch
● APs must use the same band and SSID and
operate on the same frequency in order to
connect to each other
● WDS is used to make bridged networks across
the wireless links and to extend the span of the
wireless network


Wireless Distribution System
● WDS link can be created between wireless
interfaces in several mode variations:
– bridge/ap-bridge – bridge/ap-bridge
– bridge/ap-bridge – wds-slave
– bridge/ap-bridge – station-wds

● You must disable DFS setting when using WDS
with more than one AP


Simple WDS Topologies


Dynamic WDS
Interface
● It is created 'on the fly' and appears under wds
menu as a dynamic interface ('D' flag)
● When the link between WDS devices goes
down, attached IP addresses will slip off from
WDS interface
● Specify “wds-default-bridge” parameter and
attach IP addresses to the bridge


Dynamic WDS Configuration
● WDS can be created between two APs, both
must have WDS (static or dynamic) feature
enabled
● APs must have
same SSID or the
“WDS ignore SSID”
feature enabled
● We must create a
bridge to use
dynamic wds feature

Bridge Creation


Dynamic WDS Lab
● Create a bridge interface with protocol-mode=rstp
● Make sure that wlan1 interface is set to “ap-bridge” mode
and choose with your neighbor an equal SSID
● Enable the dynamic WDS mode on the wlan1 and specify
the default-wds-bridge option to use bridge1
● Add 10.1.1.XY/24 IP to the bridge interface
● Check your network: From Your router try to ping
neighbors router
● Optional: Add ether1 to the bridge and change laptops IP
to 10.1.1.1XY/24


Static WDS
● It should be created manually
● It requires the destination MAC address and
master interface parameters to be specified
manually
● Static WDS interfaces never disappear, unless
you disable or remove them


Static WDS
● To use static WDS
use “ap-bridge” mode
● Set WDS mode to
“static” and WDS
default bridge to
“none”
● Create static WDS
interfaces


Static WDS Interface


Static WDS Lab
● Adjust setup from the previous lab, to use WDS
static mode
– Configure your wireless card accordingly
– Create the static WDS interface
– Add necessary ports to the bridge
● Optional: Add ether1 to the bridge and change
laptops IP to 10.1.1.1XY/24


Simple MESH using WDS


WDS MESH


Simple MESH


Dual Band MESH


MESH Network


MikroTik Nstreme
● Nstreme is MikroTik's
proprietary (i.e.,
incompatible with
other vendors)
wireless protocol
created to improve
point-to-point and
point-to-multipoint
wireless links.


Nstreme Protocol
Benefits of Nstreme protocol:
● Client polling
● Very low protocol overhead per frame allowing
super-high data rates
● No protocol limits on link distance
● No protocol speed degradation for long link
distances
● Dynamic protocol adjustment depending on
traffic type and resource usage


Nstreme Protocol: Frames
● framer-limit - maximal frame size
● framer-policy - the method how to combine frames.
There are several methods of framing:
● none - do not combine packets
● best-fit - put as much packets as possible in one frame,
until the limit is met, but do not fragment packets
● exact-size - same as best-fit, but with the last packet
fragmentation
● dynamic-size - choose the best frame size dynamically


Nstreme Lab
● Restore configuration backup file
● Route your private network together with your
neighbor's network
● Enable N-streme and check link productivity
with different framer polices


Nstreme Dual Protocol

● MikroTik proprietary (i.e., incompatible with other vendors)
wireless protocol that works with a pair of wireless cards
(Atheros chipset cards only) – one transmitting, one
receiving


Nstreme Dual Interface
● Set both wireless cards
into
“nstreme_dual_slave”
mode
● Create Nstreme dual
interface (press “plus”
button in wireless
interface window)
● Use framer policy only if
necessary


Winbox: Wireless Regulations


Wireless Regulations
● To follow all the regulations in your wireless
communication domain you must specify:
– Country where wireless system will operate
– Frequency mode to regulatory domain – you will be
able to use only allowed channels with allowed
transmit powers
– Antenna gain of antenna attached to this router
– DFS mode – periodically will check for less used
frequency and change to it
– (Proprietary-extensions to post-2.9.25)


Wireless Country Settings Lab
● Open terminal
● Issue “/interface wireless info print” command
● Change country to “australia”
● Issue “/interface wireless info print” command
● Compare results
● Set country back to 'no_country_set'


VPN Benefits
● Secures communications between corporate
private LANs over
– Public networks
– Leased lines
– Wireless links
● Corporate resources (e-mail, corporate
servers, printers) can be accessed securely by
users having granted access rights from
outside (home, while traveling, etc.)


Simple Tunneling Protocols

● Simple in configuration!
● Do not require authentication
● Do not use data encryption
● Such protocols are:
– IPIP (IP over IP)
– EOIP (Ethernet over IP)
– VLAN (Virtual LAN)


EoIP Tunnels
● MikroTik proprietary protocol.
● Encapsulates Ethernet frames into IP protocol
47/gre packets.
● EoIP interface supports all features of an
Ethernet interface.
● EoIP Tunnel may be run over any connection
that supports IP
● Maximum number of EoIP tunnels is 65535


EoIP and Bridging
● EoIP Interface can be bridged with any other
EoIP or Ethernet-like interface.
● Main use of EoIP tunnels is to transparently
bridge remote networks.
● EoIP protocol does not provide data
encryption, therefore it should be run over
encrypted tunnel interface, e.g., PPTP or
PPPoE, if high security is required.


Creating EoIP Tunnel


EOIP and Bridging

Any IP network
(LAN, WAN, Internet)

Bridge Bridge

Local network Local network
192.168.0.1/24 - 192.168.0.100/24 192.168.0.101/24 - 192.168.0.255/24

IPIP Tunnels
● Simple protocol to create tunnel by
encapsulating IP packets in IP packets and
sending over to the network to another router.
● RouterOS implements IPIP tunnels according
to RFC 2003.
● Uses IP protocol 4
● Maximum number of IPIP tunnels is 65535


Adding IP Addresses
● IP addresses are added to the tunnel
interfaces
– Use /30 network to save address space, for
example:
● 10.1.6.1/30 and 10.1.6.2/30 from network 10.1.6.0/30
– It is possible to use point to point addressing, for
example:
● 10.1.6.1/32, network 10.1.7.1
● 10.1.7.1/32, network 10.1.6.1


EoIP and /30 Routing
EOIP2: 2.2.2.2/30 EOIP3: 3.3.3.2/30

Any IP
network
(LAN, WAN, Internet) EOIP1: 1.1.1.1/30
EOIP2: 2.2.2.1/30
EOIP3: 3.3.3.1/30
EOIP1: 1.1.1.2/30

EoIP and /32 Routing
EOIP2: 2.2.2.2/32
Network: 1.1.1.1 EOIP3: 3.3.3.2/32
Network: 1.1.1.1

Any IP EOIP1: 1.1.1.1/32
network Network: 1.1.1.2
EOIP2: 1.1.1.1/32
(LAN, WAN, Internet) Network: 2.2.2.2
EOIP1: 1.1.1.2/32 EOIP3: 1.1.1.1/32
Network: 1.1.1.1 Network: 3.3.3.2

VLAN interfaces
● VLAN is an implementation of the 802.1Q
protocol
● VLAN allows multiple Virtual LANs on a single
ethernet cable
● VLAN supports up to 250 vlan interfaces per
ethernet device


Creating VLAN


Point-to-Point Protocol Tunnels
● A little bit sophisticated in configuration
● Offer user authentication
● Permit data encryption
● Such protocols are:
 PPPoE (Point-to-Point Protocol over Ethernet)
 PPTP (Point-to-Point Tunneling Protocol)
 L2TP (Layer 2 Tunneling Protocol)


PPPoE Tunnels
● PPPoE is used to hand out IP addresses to
clients after authentication
● PPPoE works in OSI layer 2 (data link layer)
● The PPPoE protocol provides extensive user
and network management, together with
accounting benefits to ISPs and network
administrators


PPPoE Server and Client
● PPPoE requires a dedicated access
concentrator (server), which PPPoE clients
connect to.
● Most operating systems have PPPoE client
software. Windows XP has PPPoE client
installed by default
● MikroTik RouterOS has both PPPoE server and
client capabilities


PPPoE Client Setup Lab
● Remove the IP address from your router's
wireless interface
● Remove the default route from the routing table
● Add a PPPoE client to the router's wireless
interface
– Use user 'demo' and password 'training'
– Check “Add Default Route” to use the PPPoE
connection as the default route


Adding PPPoE Client (1/2)


Adding PPPoE Client (2/2)


PPPoE Client Status
● Check your PPPoE connection
– Is the interface enabled?
– Is it “connected” and running (R)?
– Is there a dynamic (D) IP address assigned to the
pppoe client interface in the IP Address list?
– What are the netmask and the network address?
– What routes do you have on the pppoe client
interface?
● See the “Log” for troubleshooting!


Can you browse?
● Commands to use from the workstation:
– C:>tracert -d 8.8.8.8 (see how far it goes)
– C:>tracert -d google.com (does it resolve the name
to an IP address?)
– C:>ipconfig /all (are the IP address, netmask,
gateway correct, what is the DNS server?)
● Commands to use from the router:
– [john@22_John] > tool traceroute 8.8.8.8
– [john@22_John] > tool traceroute google.com


* PPPoE Lab with Encryption *
● The PPPoE access concentrator is changed to
use encryption now
● You should use encryption, either
– change the ppp profile used for the pppoe client to
'default-encryption', or,
– modify the ppp profile used for the pppoe client to
use encryption
● See if you get the pppoe connection running


PPPoE Server
● PPPoE server accepts PPPoE client
connections on a given interface
● Clients can be authenticated against
– the local user database (ppp secrets)
– a remote RADIUS server
– a remote or a local MikroTik User Manager
database
● Clients can have automatic data rate limitation
according to their profile


Adding PPPoE Server
● To enable the PPPoE server on the router
– Click the “PPP” menu in WinBox
– Select the “Interfaces” tab
– Press “PPPoE Server” button to open up the
PPPoE Server list
– Click “+” to add a PPPoE Server
– Select the interface (ether1) for PPPoE server and
click “OK”


PPPoE Server Settings


IP Pool Settings
● IP pools define the range of IP addresses used
for DHCP server and Point-to-Point servers
● It is a single configuration point for all facilities
that assign IP addresses to clients.
● It is possible to assign specific addresses for
some clients under /ppp secret, or in RADIUS
server.


Adding an IP Pool
● Go to “IP” > “Pool” and click “+” in WinBox
● Specify range(s) of IP addresses


PPP Secret and Profile
● PPP profiles define default values for user
access records stored under /ppp secret
submenu
● PPP secret (aka local PPP user database)
stores PPP user access records with PPP user
profile assigned to each user.
● Settings in /ppp secret user database override
corresponding /ppp profile settings


PPP Profile
● Go to “PPP” > “Profile” in WinBox
● Click “+” to add a new profile, or, edit an
existing one
– “Local Address” will be used on the server's side of
PPPoE tunnel, set it to the IP address of the router,
e.g., 10.1.1.22, or, any other IP address, say,
192.168.22.254 (not important)
– “Remote Address” will be assigned to the PPPoE
clients, set it to “pool1”


Editing the PPP Profile


PPP Secret
● Go to “PPP” > “Secret” in WinBox and add a
new secret for PPPoE client
– Specify “Name” and “Password” for the client
– Leave “Service” as “any”, or specify “pppoe”
– Specify the profile to be used (the one you added or
edited)


Adding a PPP Secret


PPPoE Server Lab
● Create a PPPoE connection between your
workstation and your router once the PPPoE
service is configured on the router
– Add a PPPoE network connection to your
workstation
– Connect to the router using the name and password
specified in PPP Secret
● Modify the connection settings to
– force mschap2 password authentication
– require data encryption

PPPoE, MTU, and MSS
● Always set the MTU value of a PPPoE interface
to at least 12 bytes less than the MTU of the
physical interface where PPPoE is running
● Make sure there is a mangle rule added for
each client or in general for all PPPoE clients to
change the MSS of TCP SYN packets


PPTP Tunnels
● PPTP (Point to Point Tunnel Protocol) provides
encrypted tunnels over IP
● PPTP requires a dedicated server, which PPTP
clients connect to
● PPTP traffic uses TCP port 1723 and IP
protocol 47/GRE
● PPTP clients are available for and/or included
in almost all OSes


Firewall Service Ports
● Enable PPTP and GRE “helpers” when using
NAT (masquerading) for PPTP clients on
private network, that are making connections to
“outside” PPTP servers
– “IP” > “Firewall” > “Service Ports”
● There are no “helpers” for VoIP SIP in V2.9.XX
● SIP “helpers” will be implemented in the 2.10
version


L2TP tunnels
● L2TP (Layer 2 Tunnel Protocol) supports
encrypted tunnels over IP
● L2TP requires a dedicated server, which L2TP
clients connect to
● L2TP traffic uses UDP port 1701 only for link
establishment, further traffic is using any
available UDP port
● L2TP clients are available for and/or included
in almost all OS


IPSec
● IPsec (IP Security) supports secure (encrypted)
communications over IP networks.
● After packet is src-natted, but before putting it into interface
queue, IPsec policy database is consulted to find out if packet
should be encrypted
● Security Policy Database (SPD) is a list of rules that have two
parts:
– Packet matching - packet source/destination, protocol and ports (for
TCP and UDP) are compared to values in policy rules, one after
another
– Action - if rule matches action specified in rule is performed:
● accept - continue with packet as if there was no IPsec
● drop - drop packet
●
encrypt - encrypt packet


Network Structure


Creating IPSec Policies


Entering IPsec Peers


Network with IPSec


HotSpot and QoS

ARP/DHCP, Proxy, QoS,
HotSpot, User Manager


Static ARP
● Static ARP entries are used to bind IP
addresses to MAC addresses of clients
● Change the arp setting for the relevant interface to
“reply-only” (Interface menu)
● Add IP address and MAC address pairs to the ARP
table (/ip arp menu)
● Note, that there are more advanced user
control methods, like PPPoE and HotSpot


IP and MAC Address Linking
● If you are concerned about someone bypassing
your IP firewall by using a different IP address,
try locking down client's IP address to the MAC
address of his network interface card
● Use static ARP entries for static IP addresses
● Configure the DHCP server to add ARP entries for
leases of dynamic addresses


DHCP
● DHCP is used for easy distribution of IP
configuration in a network.
● It is insecure, thus constrained to trusted
networks
● DHCP server always listens on UDP 67 port,
DHCP client - on UDP 68 port.
● Initial negotiation sequence
0.0.0.0 → ANY
ANY → 255.255.255.255
0.0.0.0 → 255.255.255.255


DHCP Client
● The client can accept:
– IP address with respective netmask
– Default gateway
– Two DNS server addresses
– Two NTP server addresses
– Domain name
– WINS-server information
● These settings will not override those you had
on your router before.


DHCP Relay

● a proxy that is able to receive a DHCP request
and resend it to the real DHCP server
● You can use one DHCP server in two LANs
simultaneously by using DHCP relays
● There can be only one DHCP relay between
client and server


DHCP Server
● An individual DHCP server for each Ethernet-
like interface
● There can be more then one DHCP server on
the one interface, but “relay” option must be
different
● You can use step-by-step DHCP server
configuration by using DHCP-server setup


IP Pool
● IP pools are used to define range of IP
addresses that is used for DHCP server and
Point-to-Point servers
● You can easily monitor used addresses
● You can specify next pool should the first one
run out of addresses


DHCP Server Networks
● Now you can create a server with your
previously created IP pool
● For DHCP additional options you must create
DHCP server networks, there you can select
DNS, NTP, WINS servers addresses
● You can also specify any other (one of 254)
DHCP option and override netmask


HTTP Proxy
● Speeds up Internet access and reduces data
flow from Internet
● Web Proxy requests information on behalf of
clients and saves it
● Successive requests will be taken from the Web
Proxy cache
● Caches HTTP and FTP connections; works as
a mediator to HTTPS connections


HTTP Proxy Features
● The MikroTik RouterOS implements the
following proxy server features:
● Regular and Transparent HTTP proxy
● Access List (HTTP firewall filter)
● Cache List (specifies which requests to cache, and
which not)
● Direct List (If parent-proxy property is specified, it
is possible to tell the proxy server whether to try to
pass the request to the parent proxy, or to resolve it
connecting to the requested server directly.)


Enabling HTTP Proxy


Transparent HTTP Proxy


Access List


Proxy HTTP Methods
● OPTIONS - method represents a request for
information about the communication options
● GET – retrieve object by URL
● HEAD – method is identical to GET except that
the server must not return a message-body in
the response
● DELETE– method requests that the origin
server delete the resource


Web-Proxy HTTP Methods (cont.)
● POST – method is used to request that the
origin server accept the entity enclosed in the
request as a new subordinate of the resource
● PUT - method requests that the enclosed entity
be stored under the supplied server
● TRACE - allows the client to see what is being
received at the other end of the request chain
and use that data for testing or diagnostic
information


Destination Host and Path
● For URL http://www.any.com/img/a1.gif
– Destination host is http://www.any.com
– Destination path is /img/a1.gif
● Special symbols can be used
– “*” is for any number of characters
– “?” is for any characters, e.g., *.mi?roti?.com


Regular Expression Mode
● Place a colon “:” at the beginning to enable
regular expression mode
● ”^“ - show that no symbols are allowed before the
given pattern
● “$“ - show that no symbols are allowed after the
given pattern
● “[....]” - A character class matches a single
character out of all the possibilities offered by the
character class
● (backslash) followed by any of [^$.|?*+() suppress
their special meaning.

Speed Limiting
● Forthright control over data rate of inbound
traffic is impossible
● The router controls the data rate indirectly by
dropping incoming packets
● TCP protocol adapts itself to the effective
connection speed
● Simple Queue is the easiest way to limit data
rate


Simple Queues

● Simple queues make data rate limitation
easy. One can limit:
– Client's rx rate (client's download)
– Client's tx rate (client's upload)
– Client's tx + rx rate (client's aggregate)

● While being easy to configure, Simple
Queues give control over all QoS features


Limits and QoS
● QoS is not only about limits
● QoS is an attempt to use the existing
resources optimally
● QoS balances and prioritizes the traffic flow
and prevents one from monopolizing the
(always too narrow) channel. That is why it is
called “Quality of Service”


Burst

● Burst is one of the means to ensure QoS
● Bursts are used to allow higher data rates for a
short period of time
● If average data rate is less than burst-
threshold, burst is enabled (actual data rate
can reach burst-limit)


Simple limitation with Burst


Average Data Rate
● Average data rate is calculated as follows:
● burst-time is being divided into 16 periods
● router calculates the average data rate of each
class over these small periods
● Note, that the actual burst period is not equal
to the burst-time. It can be several times shorter
than the burst-time depending on the max-limit,
burst-limit, burst-threshold, and actual data rate
history (see the graph example on the previous
slide)

Burst Lab
● Limit your laptop's upload/download speed
● max-limit to 64Kbps/128Kbps
● burst-limit up to 128Kbps/256Kbps
● burst-threshold 48Kbps/96Kbps
● burst-time 10 seconds
● Try downloading and see how the burst works
after you haven't downloaded for some time
● Monitor the traffic of the queue


Burst Lab (cont.)
● Following what was required in the previous
slide, try to
● change the burst-threshold to 256kbps/512kbps
● change the burst-threshold to 96kbps/192kbps
● Compare the results


Dual Limitation
● Double limitation has two data rate limits:
– CIR (Committed Information Rate) - data rate that
is guaranteed to a flow in a worst case scenario
(limit-at argument value)
– MIR (Maximal Information Rate) - maximal data
rate that is allowed for a flow to reach in the best
case scenario, if there is spare bandwidth available
(max-limit argument value)


Parent Queue Lab
● Make a “main” queue
– max-limit to 256Kbps/512Kbps
● Make a “child” queue to the “main” queue that
limits your laptop's upload/download
– parent “main” queue
– limit-at 128Kbps/256Kbps
– dst-address <first test server>


Parent Queue Lab (cont.)
● Make a second “child” queue to the “main”
queue that limits your laptop's upload/download
– parent “main” queue
– limit-at 128Kbps/256Kbps
– dst-address <second test server>


Priority
● Allows to prioritize different data flows
● 8 is the lowest priority, 1 is the highest
● Distinction between priorities is irrelevant (two
queues with priorities 1 and 8, will have same
relation as two queues with priorities 1 and 2)
● Queue with higher priority will reach its CIR
before the queue with lower priority
● Queue with higher priority will reach its MIR
before the queue with lower priority

Priority Lab
● Repeat previous lab, but this time use priorities
● Compare the results


Queuing Disciplines
● Queuing disciplines can be classified into two
groups by their influence on the traffic flow –
schedulers and shapers
● Scheduler queues reorder the packet flow.
These disciplines limit the number of waiting
packets, not the data rate
● Shaper queues control data flow speed. They
can also do a scheduling job


Shapers


Schedulers


Queue Types
● Scheduler queues
– BFIFO
– PFIFO
– RED
– SFQ
● Shaper queues
– PCQ
– HTB


FIFO Algorithm
● PFIFO and BFIFO
● FIFO queuing
disciplines do not
change packet order,
they just accumulate
packets until a
defined limit is
reached


RED Algorithm
● Random Early Detect (Random Early Drop)
● Does not limit the speed; indirectly equalizes
users' data rates when the channel is full
● When the average queue size reaches min-
threshold, RED randomly chooses which
arriving packet to drop
● If the average queue size reaches max-
threshold, all packets are dropped


RED Algorithm

● If real queue size is
much greater than max-
threshold, then all
excess packets are
dropped


SFQ Algorithm
● Stochastic Fairness Queuing (SFQ) cannot
limit traffic at all. Its main idea is to equalize
traffic flows when your link is completely full.
● The fairness of SFQ is ensured by hashing
and round-robin algorithms
● Hashing algorithm is able to divide the session
traffic in up to 1024 sub queues, if there are
more, some of them will have to skip the round
● The round-robin algorithm dequeues allot
bytes from each sub queue in a turn

SFQ algorithm

 After perturb seconds the
hashing algorithm changes
and divides the session
traffic to other subqueues


PCQ Algorithm
● Per Connection Queue allows to choose
classifiers (one or more of src-address, dst-
address, src-port, dst-port)
● PCQ does not limit the number of sub flows
● It is possible to limit the maximal data rate that
is given to each of the sub flows
● PCQ is memory consumptive!!


PCQ Algorithm

If you classify the packets by
src-address, then all packets
with different source IP
addresses will be grouped
into different subqueues

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