[KLUG Members] RE: Re: Mailog error 127.0.0.1: Host not found?!# (Peter Buxton)

[Bob Kanaley]

Peter,

Many thanks for the mild kick in the rear to get me off my duff.

I had to go back to my notes and references to check why I had done some of
the things I had done. In the process, I was able to find the problem. The
default name server did have a bad IP addresses for localhost, but it never
should have been my default nameserver. The default name server was third
down the list!!!

A short time ago, I had to do some quick stepping when my previous ISP
dropped business service with no notice. I had to scramble to get a new ISP
that would give me a static IP on a dedicated dialup and get my new MX
record out in DNS. In case things didn't work out and I had to do a quick
switch back, I left my old ISP name servers in resolv.conf. After being down
three days, there was a lot of email streaming into my server and I didn't
want to touch anything till I cleared the backlog. As usual I got busy and
never looked back.

When I started checking to see why the third nameserver was being used as
the default name server, I found that the new ISP name server records, given
to me over the phone, were incorrect. I used nslookup pointing to a good
name server and dig to come up with the correct NS records for my new ISP. I
put these in resolv.conf and dropped the old and worthless entries.
localhost now resolves with no errors, as does 127.0.0.1.

Thanks for the help.

Regards,

Bob

Robert V. Kanaley
Manager Information Systems
Agdia, Inc.
rvk@agdia.com
http://www.agdia.com



> > [root@dmz02 /etc]# cat resolv.conf
> > search agdia.com
> > # nameserver 207.32.234.10
> > nameserver 207.32.234.11
> > nameserver 209.172.192.26
> > nameserver 209.172.194.2
> > nameserver 209.172.192.2
> > nameserver 209.84.160.105
> > nameserver 0.0.0.0
> > # nameserver 127.0.0.1
> > # nameserver 192.168.2.2
>
> Scary resolv.conf. That's a lot of nameservers. And what exactly does
> "nameserver 0.0.0.0" do for you??

<aside/ I believe  the 0.0.0.0 entry was was from a suggestion by Cricket
Liu on the BIND list. It was an attempt to resolve a DNS problem I was
having at that time. In O'Reilly's DNS and BIND 3rd Edition by Palul Albitz
and Cricket Liu, chapter 6 Configuring Hosts, under The nameserver
Directive, on page 106 it says "The zero address, 0.0.0.0, is interpreted by
most TCP/IP implementations to mean 'this host.'". /aside>