nslookup gives "connection timed out; no server could be reached"
I am pretty new to Linux/networking, so please bear with me.
I have a SLES that I use as a webserver. It has the IP address 10.108.15.133 and subnet mask 255.255.252.0. I have recently moved this server into my DMZ because I run a web application on this server, and want to keep the server in a different network from my company network. When I type: > nslookup XXX (where XXX is some machine in my company network) I get the following: > nslookup XXX ;; connection timed out; no servers could be reached I have used Yast2 to set my name server to 10.108.11.224, which is the DNS server for the company network. I understand the cause of this problem could lie in many areas. E.g.: 1. nslookup not configured on the SLES 2. firewall preventing nslookup from using a DNS server sitting in a different network. 3. etc. Why does nslookup not work from my SLES sitting in the DMZ? Is there any tests that I can do help me identify where the problem lies? Thanks in advance. |
1. I would suspect that firewall prevents the dns traffic to flow freely between DMZ and LAN.
2. I would also check if DNS service is up and running on the nameserver. Boris. |
1. What port do I need to open up to allow dns traffic to flow freely between DMZ and LAN?
2. How do I check if DNS service is up and running on the nameserver? |
you need to allow traffic from DMZ to nameserver on LAN on UDP port 53.
the easiest way to find out if dns is working on the nameserver is dig @localhost hostname and see if you get a result back if you are using BIND you can check with ps -ef|grep [n]amed and see if the process is running |
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