[Samba] Reverse DNS question

[Christian Cryder]

Hi folks!

Ok, I'm at my wits end here and I'm hoping someone can give me some pointers
in the right direction. I am running RedHat 7.2 as a PDC (Samba 2.2.1a),
with Postfix for my SMTP server, and UW's Imap server for POP. I'm not
running a DNS server on this machine (DNS services come from our upstream
ISP). Here's what I'm observing:

1. From the local network...When I try to SSH into the linux box, connect
via POP, send mail, or log into the domain, it frequently takes up at least
30 seconds to establish a connection.

2. From the outside world...When I try to SSH into the linux box, connect
via POP, or send mail, its a snap (just a few seconds at most) to connect to
the box.

It almost seems as if something on the box is trying to do reverse dns
lookups on private IPs. I've been searching in vain to try and figure out
what controls this and how to either
a) configure it to not do reverse dns on private ips, or
b) turn off reverse dns altogether.

I've searched all the specific application conf files for Postfix, Samba,
SSH, etc, and can't find anything. The fact that this slowness is affecting
all of these programs seems to suggest that the problem is occurring at some
lower level that they all use. Unfortunately, I'm at a loss as to where to
look next.

On a similarly configured box, where the only difference is that Samba is
not acting as a domain controller, I don't experience any slowdowns, both
for internal and external access. SO...does this sound like a Samba related
issue? Or do I need to look elsewhere (if so, where).

tia,
Christian
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Christian Cryder [christianc at atmreports.com]
Internet Architect, ATMReports.com
Barracuda - http://barracuda.enhydra.org
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 "What a great time to be a(n employed) Geek"