[svlug] High availability mail server

John Conover conover at inow.com
Tue May 11 19:00:35 PDT 1999

John Conover writes:
> Neat, George. Might try tcpserver to limit the number of concurrent
> connections to port 25 in each machine. Works with sendmail, qmail,
> and exim. My rc start looks like:
>     tcpserver -R -x /my/path/access/tcp.smtp.cdb -u 504 -g 101 0 smtp /var/qmail/bin/qmail-smtpd &
> for qmail, (same for sendmail, only the path changes, and uid and
> gid,) where tcp.smtp.cdb controls access, (only used if necessary,)
> and restricts the concurrent sessions to 40, (programmable from the
> command line,) and then pushes to the next MX.

BTW, I actually run email logging, (so if one of my users spams, and
the bounces slow down the mail queue, I can find the offender.) The
syslog daemon is a bit slow, (and I don't want heavy email traffic in
it,) so I really use:

    tcpserver -R -v -x /my/pathaccess/tcp.smtp.cdb -u 504 -g 101 0 smtp \
        /var/qmail/bin/qmail-smtpd 2>&1 | /var/qmail/bin/splogger smtpd 3 &

Splogger is kind of nice in that it automatically moves the log file,
(after it gets so big,) to another file, and starts a new one
automatically. So, one can move the completed log files out of the
system via daemon, and keep them for awhile for future reference in
case I have to catch someone. It is, also, very fast and requires
minimal sys resources.

I use tcpserver/syslogger on the minimal set of inet services I run
instead of inetd, (ie., pop3, telnet, ftp, http, and smtp.) So, all
access is controlled through a highspeed database, and transactions
logged. Tcpserver has options to require ident, ip verification, etc.,
if required, and can control smtp relaying on a per user/per
machine/per network basis, (so one can mail to users, but not relay
through the machine-you would be surprised the attempts one finds in
the logs. Not fool proof, by any means, a little better.)

Works OK for me ...



John Conover, 631 Lamont Ct., Campbell, CA., 95008, USA.
VOX 408.370.2688, FAX 408.379.9602, whois '!JC154'
conover at inow.com, http://www2.inow.com/~conover/john.html

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