irc.freenode.com e irc.ubuntu.com referem-se à mesma coleção de servidores irc. Ambos são CNAMEs (DNS aliases) para chat.freenode.net. A configuração atual é a seguinte
andreas@stilgar:~$ host irc.freenode.com
irc.freenode.com is an alias for chat.freenode.com.
chat.freenode.com is an alias for chat.freenode.net.
chat.freenode.net has address 93.152.160.101
chat.freenode.net has address 82.96.64.4
chat.freenode.net has address 208.82.117.76
chat.freenode.net has address 213.92.8.4
chat.freenode.net has address 213.232.93.3
chat.freenode.net has address 130.239.18.172
chat.freenode.net has address 38.229.70.20
chat.freenode.net has address 84.240.3.129
chat.freenode.net has address 89.16.176.16
chat.freenode.net has address 130.237.188.200
chat.freenode.net has address 94.125.182.252
chat.freenode.net has address 50.22.136.18
chat.freenode.net has address 78.40.125.4
chat.freenode.net has address 140.211.167.98
chat.freenode.net has address 140.211.167.99
chat.freenode.net has address 216.155.130.130
chat.freenode.net has address 86.65.39.15
chat.freenode.net has address 213.179.58.83
chat.freenode.net has IPv6 address 2001:19f0:feee::dead:beef:cafe
chat.freenode.net has IPv6 address 2a03:280:0:1::1
chat.freenode.net has IPv6 address 2001:1418:13:1::25
chat.freenode.net has IPv6 address 2a02:2498:3a3:1b96::1
chat.freenode.net has IPv6 address 2001:820:2::6
chat.freenode.net has IPv6 address 2001:6b0:5:1688::200
chat.freenode.net has IPv6 address 2001:6b0:e:2018::172
andreas@stilgar:~$ host irc.ubuntu.com
irc.ubuntu.com is an alias for chat.freenode.net.
chat.freenode.net has address 213.232.93.3
chat.freenode.net has address 94.125.182.252
chat.freenode.net has address 140.211.167.98
chat.freenode.net has address 208.82.117.76
chat.freenode.net has address 216.155.130.130
chat.freenode.net has address 78.40.125.4
chat.freenode.net has address 140.211.167.99
chat.freenode.net has address 50.22.136.18
chat.freenode.net has address 213.92.8.4
chat.freenode.net has address 130.237.188.200
chat.freenode.net has address 84.240.3.129
chat.freenode.net has address 89.16.176.16
chat.freenode.net has address 82.96.64.4
chat.freenode.net has address 213.179.58.83
chat.freenode.net has address 86.65.39.15
chat.freenode.net has address 130.239.18.172
chat.freenode.net has address 38.229.70.20
chat.freenode.net has address 93.152.160.101
chat.freenode.net has IPv6 address 2a02:2498:3a3:1b96::1
chat.freenode.net has IPv6 address 2001:6b0:e:2018::172
chat.freenode.net has IPv6 address 2001:6b0:5:1688::200
chat.freenode.net has IPv6 address 2001:19f0:feee::dead:beef:cafe
chat.freenode.net has IPv6 address 2001:820:2::6
chat.freenode.net has IPv6 address 2001:1418:13:1::25
chat.freenode.net has IPv6 address 2a03:280:0:1::1
andreas@stilgar:~$