Related to sendmail "gethostbyaddr" error

[Jack Berger]

I don't believe that the sendmail.cf file points to a dns server. I
could be totally wrong on this though. The first thing I would check
is where the mailserver gets its dns info.

What do you get when you do an nslookup from the mail server? It
should tell you what nameserver it is using. as in:

jhb at bob:~> nslookup thor.nowhere.org
Server:  castor.nowhere.org   << this is the dns server it is using
Address:  141.141.1.60        << and its address

Name:    thor.nowhere.org     << the system you are querying for
Address:  141.141.22.200      << and its address

Your resolv.conf should look like this:

jhb at bob:~> more /etc/resolv.conf
nameserver 141.141.1.60   << primary dns
nameserver 141.141.1.61   << secondary dns

Also, check to see that the server is not still running named (the dns
daemon). If it is that may be screwing things up.

-jhb-


====================================================================================
From:    Swapana Ghosh <swapana_ghosh at yahoo.com>

    No i  have not touched anything in the mailserver. Could you
please guide
me how to point the mailserver to the new DNS server... This is the
cobalt
server so i generally don't touch the sendmail.cf file... Anyway it
will be
helpful if you say me how i will pointed sendmail to check the reverse
PTR
where the new nameserver is looking into....

    I have checked the resolv.conf file the first entry is showing the
server
ip address. Where as the new nameservr has the ip addresses of the
provider....

 Thanks again
-Swapna