Doing horrible things to DNS involves using CNAME records to create multiple domain names that resolve to the same IP addresses. This allows making a single DNS query but receiving responses for multiple domains, enabling more parallel HTTP requests. The technique involves creating a chain of CNAME records that ultimately resolve to a single canonical name, gaining the ability to load resources from different apparent hostnames while only requiring one DNS lookup.
46. enki:~ $ dig yahoo.com
; <<>> DiG 9.4.3-P3 <<>> yahoo.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32801
;; flags: qr rd ra; QUERY: 1, ANSWER: 5, AUTHORITY: 7, ADDITIONAL: 7
;; QUESTION SECTION:
;yahoo.com. IN A Query
;; ANSWER SECTION:
yahoo.com. 5935 IN A 69.147.125.65
yahoo.com. 5935 IN A 72.30.2.43
yahoo.com. 5935 IN A 98.137.149.56
yahoo.com.
yahoo.com.
5935
5935
IN
IN
A
A
209.191.122.70
67.195.160.76 Response
...
;; Query time: 45 msec
;; SERVER: 202.171.190.10#53(202.171.190.10)
;; WHEN: Wed Oct 13 17:23:39 2010
;; MSG SIZE rcvd: 345
47. ajax1.hackerhouse.org. 1800 IN CNAME ajax2.hackerhouse.
ajax2.hackerhouse.org. 1800 IN CNAME ajax3.hackerhouse.
ajax3.hackerhouse.org. 1800 IN CNAME ajax4.hackerhouse.
ajax4.hackerhouse.org. 1800 IN CNAME ajax.hackerhouse.
ajax.hackerhouse.org. 1800 IN A 192.168.1.1
ajax.hackerhouse.org. 1800 IN A 192.168.1.2
ajax.hackerhouse.org. 1800 IN A 192.168.1.3
ajax.hackerhouse.org. 1800 IN A 192.168.1.4
ajax.hackerhouse.org. 1800 IN A 192.168.1.5