I don't know of a standalone one that costs less than $1500
The only solution I have for you is exactly what you don't want:
A Soekris engineering single board computer running linux or freebsd and 
a program that forwards the mail whilst checking the spam-DNS sevices.
Sorry that's all I've got, I know you wanted something easier.
http://www.soekris.com/net4501.htm
--
Martin Klingensmith


James Newton, Host wrote:

>Sort version:
>
>Is there a firewall / router that will check incoming requests on port 25
>against a list of RBLs and reject the ones that are listed? Preferably with
>a message about RBLs and how to get off them.
>
>Long version:
>
>I'm getting buried in spam.
>
>No surprise considering how many public email addresses I have.
>
>I have some pretty good spam filters and I use the RBLs via software on the
>POP3 side. It helps a lot and things are more or less livable.
>
>But I would really like to move the RBL blocking to the /other/ side of the
>email server: On the internet side of the server. Two reasons:
>
>A) That way the server doesn't have to store and POP3 the spam and it can
>instead be dumped before it even gets to clients. 
>
>B) So that any false positives know that their email was rejected.
>Hopefully, along with a quick explanation of why and some advice on how to
>fix it or a link to a web contact form if they can't.
>
>Now there are undoubtedly many fine email server programs that will do just
>that but I don't really want to install and learn a new one at this time. 
>
>I've found a program that can perhaps be installed on the server and setup
>to pick up connections on some port other than 25 (port forwarded by the
>router) and then send them on to port 25 on the same server if they pass.
>E.g. the router would forward 25 to 2525 and this software would pick up
>those requests, check them against the RBLs and then forward them to
>127.0.0.1:25 if they pass.
>
>But it seems like that is a function that would fit very nicely into a
>firewall or router. I'm less than impressed with the one that I have now and
>I'm wondering if I can kill two birds with one stone.
>
>Thanks for your advice.
>
>---
>James Newton: PICList webmaster/Admin
>mailto:jamesnewton@piclist.com  1-619-652-0593 phone
>http://www.piclist.com/member/JMN-EFP-786
>PIC/PICList FAQ: http://www.piclist.com
>
>
>  
>

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