DNS mapping to specific DNS server.

[lisadone]

hi

how can I test the DNS mapping to specific DNS server.

I just got doubt on my dns server.

I just checked with nslookup but it replieing proper server ip, but I want to check whether its repying correct port number or not. becuase its getting delay while in name resolution.

advance thanks.

yours

lisa

[ohno]

The client only expects to receive DNS replies from UDP port 53. As you are getting a respone the port number shouldn't be a problem.

You can try this command on the DNS server (for your eth0 NIC) to see the DNS traffic.

tcpdump -n -i eth0 port 53

The delay may be because you have multiple DNS servers defined in your client's resolv.conf file, and one of the servers isn't responding. You can use this command to test DNS queries against a specific host, and see whether it has the right answers. It will help eliminate bad DNS servers and you don't have to be the root user to do it.

# host wedsite-name dns-server-ip-address

[Kernel_Killer]

dig @<server ip> host.recordyouarelookingup.com

That's a great way to check the DNS A records, and to see if the right DNS servers are being delegated to, and what IP it says the host is from the DNS server itself.