0

Regards,

I've run into the following issue recently following an intrusion in to my VPS:

Although resolv.conf is properly configured with the correct DNS servers the VPS can not resolve hosts.

I can:

  • Ping the DNS Servers just fine
  • I can ping based on IP

I can not:

  • Resolve hostnames
  • ping the hostname of the actual localhost / server.

I've tried looking into where the problem may lie but I see no rules, for instance, blocking outgoing DNS traffic.

Results of nslookup google.com

hostname:/etc/network# nslookup google.com
;; connection timed out; no servers could be reached

I'm slowly running out of ideas on where to look.

Any ideas ?

Thanks in advance,

0

The first thing to check is to see if the DNS request is actually leaving for the right destination.

Open 2 terminal sessions. On one type:

# tcpdump -nn port 53

on the other do the:

# nslookup google.com

The one with the tcpdump command should show you something like the below when all is working fine:

16:39:10.047709 IP 9.15.165.24.57618 > 192.168.1.254.53: 21549+ A? google.com. (28)
16:39:10.074647 IP 192.168.1.254.53 > 9.15.165.24.57618: 21549 1/0/0 A 216.58.216.14 (44)

If you do not even see the outgoing packet, then there is an internal problem with the name resolution config on your server.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.