If you're going to run an open relay, don't run it on port 25. Run it on
1025 or some other high port, and only let your customers know what the port
is.
Yes, this is security through obscurity, but it should keep spammers from
finding your relay.
And, like everyone else is saying, RTFM.
--Adam
-----Original Message-----
From: Martin Staael <[EMAIL PROTECTED]>
To: Petr Novotny <[EMAIL PROTECTED]>
Cc: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Date: Wednesday, February 03, 1999 9:26 AM
Subject: Re: Filters with qmail
:Petr,
:
:At 15:11 03-02-99 +0000, you wrote:
:
:>1. If your customers have static IP, setup a database for tcpserver
:>which exports RELAYCLIENT="" for those special IPs (see FAQ 5.4)
:
:They don't. The use dial-in from around the world.
:
:What I need is a program to check that a user is not sending more than xx
:mails within yy minutes. (ie. 30 mails within 5min).
:
:It would be nice if a program could do a match on the mails - so that if
:someone has send 5 mails in a row that a program did match the previous
:mail - and if at least 70% percent of the previous mail were matched then
:this mail would probally be spam. With spam mails normally the
:receiver/sender and some of the content is changed. So it is actually very
:easy to do a match whether a mail is spam - if just enough of these has
:been sent.
:
:Can you follow this?
:
:>2. If your customers ahve dynamic IPs (or connect from all around
:>theh world), go to www.qmail.org and find there Open-SMTP patches (in
:>fact it means that after successful POP3 authentication, you open a
:>relay for that IP for some time - like 5 or 10 minutes).
:
:I have considered this solution. But most POP3 clients such as Netscape and
:Eudora actually DO send mail by SMTP first, rather than checking mail
first.
:
:I'm really without a clue here. I hope someone has developed as spam filter
:that do a match on mails - for preventing spam or check whether the host is
:sending more than xx mails within yy min.
:
:Martin,
:
