topic Re: dns headache in Operating System - HP-UX

dns headache

steven Burgess_2 — Thu, 09 Jun 2005 12:15:49 GMT

Hi everyone

I have an external address that I can resolve through DNS, returned are 5 ip addresses for the one host

When I try to

telnet 25

or

ping

I get the message "unknown host"

I have this working ok on linux and windowz

I have the domain set in /etc/resolv.conf

I have my ip,fqdn and host set in /etc/hosts for the localhost

Any ideas why this is not working

Regards

Steve

Re: dns headache

D Block 2 — Thu, 09 Jun 2005 12:34:03 GMT

steve, did someone change your /etc/nsswitch.conf file ?

Re: dns headache

Geoff Wild — Thu, 09 Jun 2005 12:37:07 GMT

Try FQDN:

telnet hostname.somedomain.com 25

Rgds...Geoff

Re: dns headache

D Block 2 — Thu, 09 Jun 2005 12:40:16 GMT

traceroute

traceroute <- should return unknown.

Re: dns headache

C. Beerse_1 — Fri, 10 Jun 2005 03:40:32 GMT

'unknown host' mostly points to host-lookup problems. If you can ping/telnet the machine by ip-address, then it is definitly host-lookup.

Try a 'nslookup' of the machine by its name and by its full name .your .domain.

If nslookup fails on both, then most likely your nsswitch (search order) and/or /etc/hosts is not properly configured. Also check what is searched in nsswitch, dns should be one of them.

If nslookup fails on but succeeds on the full name, update /etc/resolv.conf with the (all) local used domainnames.

Re: dns headache

Muthukumar_5 — Fri, 10 Jun 2005 03:53:24 GMT

What you are getting for,

nslookup

what is in /etc/nsswitch.conf file for hosts: entry.

nsquery

what you are getting there.

Check tracerouting path with,

tracert(windows) or traceroute (unix)

hth.

Re: dns headache

Suraj Singh_1 — Fri, 10 Jun 2005 04:49:04 GMT

Files you need to look for:

i) /etc/rc.config.d/netconf
Check if the IP Address, Netmask and default gateway is set up correctly.

ii) /etc/resolv.conf
Check the DNS server's entry, it should have at least one line:

nameserver xx.xx.xx.xx ; Enter the DNS servers IP address here

iii) /etc/nsswitch.conf
Look for the line starting with "hosts", it should be something like:
hosts: dns [NOTFOUND=return] nis [NOTFOUND=return] files
NOTE: You may remove nis portion if nis is not configured in your environment.

~Suraj

Re: dns headache

steven Burgess_2 — Fri, 10 Jun 2005 08:02:52 GMT

Tom get's the rabbit

The plonker that added the entries to /etc/nsswitch.conf disregarded the entry that was already in there. When I built the machines here on site I had to force files as we didn't have dns setup. He added a new entry at the bottom of the file which was correct but was never referenced as the initial entry took precedence.

Thanks everyone

Steve