Page History

...

Let's try the hard way to secure our mailsystems. Not as convenient as using spamd and spamc is the approach mentioned in the postfix FilterReadme. Some guys at http://www.WorldDesign.com/index.cfm/rd/mta/spampd.htm have published a spamd replacement that works as a SMTP-proxy. The advantage over spamd/spamc is that problems with either PERL, Spamassassin or it's configuration don't lead to lost mail. The SMTP-proxy is designed to reject mail in case of non-recoverable faultsefficiency (no fork/exec()ed processes or temporary files required for failsafe operation) and the ability to use before-queue content filtering.

It can easily be integrated as a "content_filter" in postfix. The knack is, that mail classified as spam is forwarded to users, where the filter of their local eMail client should detect the spam-status. Goal should be to forward spam to a special user named "spamking". This could be done by using an alias-map for all users that like their spam removed. The solution described here is for a Mail-server with a limited number of users with varying knowledge. All users are "local", meaning they get their mail via POP/IMAP from the mailserver.

...

#!/bin/sh
sa-update && /etc/init.d/spampd restart
true

• Wiki Markup
  Scott Lamb writes: "The cron script

  must also restart spampd for the changes to take effect. I don't know the Ubuntu command, but on RedHat-based distributions, sa-update && /sbin/service spampd restart will do. (sa-update returns false if no updates were available.) This might cause mails in progress at the time to get a 4xx failure with "queue file write error" because spampd does not support graceful restarts. That's harmless; the remote system will retry. - Slamb

  must \[...\] restart spampd for the changes to take effect. \[...\] on [RedHat]-based distributions, {{sa-update && /sbin/service spampd restart}} will do. (sa-update returns false if no updates were available.) This might cause mails in progress at the time to get a 4xx failure with 'queue file write error' because spampd does not support graceful restarts. That's harmless; the remote system will retry." \\

(6) Edit /etc/postfix/master.cf. The following replaces the initial "smtp" entry:

...

Naturally, other distributions will require variations from this procedure.

• RodRoark

Handling Large Emails

By default, spampd passes through all emails over 65536 bytes. This is set by --maxsize. Increasing this limit can cause problems on systems with very little RAM. Larger email can be blocked by postfix with the main.cf option:

message_size_limit = 65536

Or you can scan all larger emails via procmail after postfix with the procmail rule:

:0fw: spamassassin.lock
* > 65536
| spamassassin

:0:
* ^X-Spam-Status: Yes
spam