Unable to receive inbound SMTP traffic through ISA Server 2000


I have the following set up.  Exchange server 2003 on windows 2003 on the internal LAN sitting behind an isa server 2000 on windows 2003.  It is a stand alone isa server acting as our firewall and connects to our ADSL router.  I use this route to the internet successfully for inbound and outbound http traffic but when I try to receive incoming smtp traffic emails don't arrive.  On the isa server I have disabled the smtp filter and tested by using the mail security wizard to publish the exchange server as well as tested configuring the isa server as a smtp relay and neither work.

Please can you advise on where I am going wrong???

Many thanks in advance
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Who is the authoratative DNS for your domain?  Do you have a MX record defined?

harbor235 ;}

neilosAuthor Commented:

Hi harbor235

We have internal and external DNS, the external DNS with the ISP has our MX record which points to our static IP provided by our ADSL connection.

The MX record is mail.domainname.com

Our local DNS configured as domainname.local

If you need more info, just yell...
What kind of machine is the email server, what mail server software are you running? Sendmail, Exchage ?
Can you telnet to port 25 from the inside network? <telnet ip_address 25> If the server is running you should be able to telnet to port 25 aqnd get a mail
banner if it is running, in addition, you will be able to ececute mail commands via the command line. If you can connect to port 25 from the inside network
you know the server is running, try this process again from the outside. If you fail to connect from the outside then the firewall is preventing the connection
and you should review your config.

harbor235 ;}

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neilosAuthor Commented:

It wasn't the port not being available but you got me thinking so I went over it all and it was the config for Exchange to become a SecureNat client, it needed to have the correct default gateway.

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