Linux – Centos 5.4 (x86_64) DNS resolution woes

bindcentos5domain-name-systemlinuxopendns

I've setup a Centos 5.4 (x86_64) box in a VM recently; the trouble is I just can't get internet to work on it.

Pinging the resolved google.com ips, nameserver ips works fine but DNS lookup queries don't.

Here's some of the digging around that I did:

dig google.com
; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5 <<>> google.com
;; global options:  printcmd
;; connection timed out; no servers could be reached

nslookup google.com
;; connection timed out; no servers could be reached

I didn't observe any UDP/TCP packets during dig and nslookup either

cat /etc/resolv.conf
; generated by /sbin/dhclient-script
nameserver 208.67.220.220
nameserver 208.67.222.222

Also my /etc/nsswitch.conf is in order and contains the "hosts: files dns"

What could be wrong?

Best Answer

  1. Rule out iptables:

    service iptables stop

Do the nslookup. If it works then inspect your ruleset and retry. Don't forget to restart iptables.

  1. Try telnetting to port 53 of those ip addresses:

    telnet 208.67.220.220 53

You should see:

$   telnet 208.67.220.220 53
Trying 208.67.220.220...
Connected to 208.67.220.220.
Escape character is '^]'.
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