Re: SMTP servers behind firewall....

From: Don Kelloway (dkelloway_at_commodon.com)
Date: 05/27/03 

Date: Tue, 27 May 2003 21:20:05 GMT

"Winter" <Respond@InThis.Group> wrote in message
news:QZKAa.114$vi4.16924@news0.telusplanet.net...
> Would this eliminate problems with the MX records as well?
>

If the A record that the MX record is specifying is entered into the
hosts file, it should alleviate the need to query DNS. This is because
the hosts file is loaded into memory/cache when the system is restarted.

IOW if an SMTP server is going to send email to someone@abc.com, the
SMTP server is going to query DNS for an MX record(s) and subsequent A
record(s). Note: The resultant A record may be something like
'smtp.abc.com' or 'mail.abc.com', etc.

If you enter the following into the hosts file:

192.168.0.1 smtp.abc.com
and/or
192.168.0.1 mail.abc.com

Try it. I believe it should work. Then again I am running a DNS on the
internal side of a NAT-enabled firewall and I haven't had the need to
populate a hosts file in a long awhile. <grin>

If I can find the time to run a quick test, I'll confirm/deny the above.
In the interim and if you want to try it yourself, go for it. 

-- 
Best regards,
Don Kelloway
Commodon Communications
Visit http://www.commodon.com to learn about the "Threats to Your
Security on the Internet".

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