A few things you can try to do as far as troubleshooting DNS.
1. Try to see if your domain has the correct entries. 'dig' is a tool that comes with bind that you can use to query DNS records. Example:
Code: Select all
burhan@phoenix ~ $ dig example.com
; <<>> DiG 9.2.5 <<>> example.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12504
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2
;; QUESTION SECTION:
;example.com. IN A
;; ANSWER SECTION:
example.com. 172800 IN A 192.0.34.166
;; AUTHORITY SECTION:
example.com. 21600 IN NS a.iana-servers.net.
example.com. 21600 IN NS b.iana-servers.net.
;; ADDITIONAL SECTION:
a.iana-servers.net. 131032 IN A 192.0.34.43
b.iana-servers.net. 131032 IN A 193.0.0.236
;; Query time: 705 msec
;; SERVER: 192.168.1.10#53(192.168.1.10)
;; WHEN: Sat Mar 11 14:39:18 2006
;; MSG SIZE rcvd: 125
The above output gives us important information. It tells us what does the computer thinks that example.com points to -- in this case, its 192.0.34.166. It also tells us the nameservers listed for that domain (a.iana-servers.net and b.iana-servers.net) and most importantly, which server it queried for the information. This is the the line after Query time:
SERVER: 192.168.1.10 <-- this is the IP address of the server that this particular workstation is using for DNS. As you can see, this is an internal IP address (I have my own DNS server running on the local network).
If you issue the same command, you will get similar output, but the information to check is what server is it resolving it from. You might want to try this for your own server's fqdn to see if it resolves correctly or not.
2. Another command that you can use, that gives similar output but is not that detailed is nslookup:
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burhan@phoenix ~ $ nslookup example.com
Server: 192.168.1.10
Address: 192.168.1.10#53
Non-authoritative answer:
Name: example.com
Address: 192.0.34.166
Here you get the server queried, and the answer recieved. Try the above with your fqdn to see if its resolving correctly.
Hope this helps you get started.