Saturday, June 14, 2008

DNS fail

I saw this host in a traceroute and had to be sure:
> server jupiter.is.co.za
Default server: jupiter.is.co.za
[snip]

> set type=ptr
> 218.115.209.168.in-addr.arpa
[snip]

218.115.209.168.in-addr.arpa name = mail.amorphous.net.

> set type=a
> mail.amorphous.net
[snip]

Name: mail.amorphous.net
Address: 196.211.13.115
168.209.115.218 != 196.211.13.115

It looks like Internet Solutions forgot some old reverse DNS records when updating things, and re-used the address for infrastructure.

1 comment:

tumbleweed said...

Can I suggest you investigate dig and host. They make DNS querying much simpler.

Host:
$ host 168.209.115.218
218.115.209.168.in-addr.arpa domain name pointer mail.amorphous.net.

# Specified resolver:
$ host mail.amorphous.net. jupiter.is.co.za
mail.amorphous.net has address 196.211.13.115

Dig:
$ dig -x 168.209.115.218

; <<>> DiG 9.4.2 <<>> -x 168.209.115.218
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 10115
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;218.115.209.168.in-addr.arpa. IN PTR

;; ANSWER SECTION:
218.115.209.168.in-addr.arpa. 85841 IN PTR mail.amorphous.net.

;; Query time: 2 msec
;; SERVER: 10.21.1.2#53(10.21.1.2)
;; WHEN: Mon Jun 23 21:10:18 2008
;; MSG SIZE rcvd: 78

# Specified resolver:
$ dig mail.amorphous.net. @jupiter.is.co.za

; <<>> DiG 9.4.2 <<>> mail.amorphous.net. @jupiter.is.co.za
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 5305
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 3
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;mail.amorphous.net. IN A

;; ANSWER SECTION:
mail.amorphous.net. 600 IN A 196.211.13.115

;; AUTHORITY SECTION:
amorphous.net. 600 IN NS jupiter.is.co.za.
amorphous.net. 600 IN NS titan.is.co.za.
amorphous.net. 600 IN NS demeter.is.co.za.

;; ADDITIONAL SECTION:
titan.is.co.za. 86400 IN A 196.33.171.36
demeter.is.co.za. 86400 IN A 196.26.5.8
jupiter.is.co.za. 86400 IN A 196.4.160.3

;; Query time: 51 msec
;; SERVER: 196.4.160.3#53(196.4.160.3)
;; WHEN: Mon Jun 23 21:11:08 2008
;; MSG SIZE rcvd: 172