I'm evaluating the possible use of SPAMFilter ISP with ArgoSoft Mail Server Plus.  I'm not very knowledgable when it comes to any of this, so please be kind with your responses!

I've set Argosoft to listen on port 26 and SPAMFilter ISP to listen on port 25.  All of the users in our building can receive e-mail fine.  When we try to send e-mails though we get an error that the IP of the sender does not have reverse DNS.  When I disable to reverse DNS check, then the sender gets an error that they are not allowed to send to whatever address.   We are able to send internal e-mails (addressed to addresses in our domain) fine.

What I'm guessing is that our outgoing e-mails need to goto Argosoft and not SPAMFilter ISP.  SO, what is the easiest way to do this?  OR am I doing something else wrong?

Thanks,
Konrad

Konrad,

SpamFilter is designed to handle incoming email traffic only. All your outgoing email should be processed by your regular SMTP server if possible. From your post it seems that you are having your users trying to use SpamFilter to handle your outgoing email as well, but SpamFilter is blocking it since out-of-the-box it will not allow relaying to the internet for security reasons.

There are several ways to configure the email flow to accomodate your environment:

Internet ---> Firewall/Router ---> SPAMfilter -->ArgoSoft SMTP Server

The simplest solution, if the firewall allows it, is the following.

Configure your firewall to accept internet email traffic on port 25, and have it perform port translation to pass it on to SpamFilter on a different port, say 26.
Configure SpamFilter to listen on port 26, which will allow it to accept email coming from the firewall. Have SpamFilter forward email to port 25 on your existing SMTP server
Leave your SMTP server's configuration unchanged, always listening on the same IP your customers have and on port 25. This way no users will have to make any changes, and they will still use your existing SMTP server for their outgoing email.

This would be the email flow:

Internet (25) --> Firewall -- (26) --> SpamFilter --(25)--> Your SMTP server

Most non-home-style firewalls should be able to perform the port translation required.

If the above is not an option, bind two different IPs to the NIC on your server. Again do not alter your existing SMTP configuration, and have SpamFilter listen on port 25 of the 2nd IP address. Then have your firewall forward email traffic (to port 25) on that 2nd IP. SpamFilter will then forward it to the IP of your SMTP server. In this way too no users will have to make any changes, and they will still use your existing SMTP server for their outgoing email.

If that also is not an option, the only solution left is to configure SpamFilter to allow your internal customers to relay to the internet. To do this, you need to add your own class C's that the users are on to the "Excluded Domains / IPs" whitelist in SpamFilter, so they will be allowed to relay using SpamFilter.

Roberto F.
LogSat Software

Thanks for the help.  We're a small company and the router we are using is one from Bestbuy, so I can't forward port 25 traffic to port 26.  I know how to bind two IP addresses to one NIC on a Win98 machine, but do not know how to do it with Windows 2000.  Is it not possible in 2000?  Do I just need two NIC cards?

Thanks,
Konrad

I figured out how to add another IP to a NIC.  But, now when I load SpamFilter, it tells me "Could not bind socket.  Address and port are already in use." 

It seems the problem I have is that I can't tell Argosoft to listen on any specific IP address.  Does anyone know how to solve this?

Konrad

Make sure that your clients are set to send outgoing mail to port 26 of the mail server, rather than the normal port 25

That's all you have to change in your current configuration.