What filters are in use?
- Route Address filter 1.0.1
- This filter will bounce any recipient that has a % or ! in it, or starts with an @.
- Period Patrol Filter
- This filter will bounce any message that contains more than 8 consecutive periods
in the message subject.
- Host Hame Filter
- This filter checks the SMTP HELO/EHLO name to see if the sending mail server is pretending
to be our email server. No legitimate email server would do this.
- Host Syntax Filter
- This filter checks the SMTP HELO/EHLO name to make sure it is compliant with
relevant standards, and refuses mail from any host that isn't compliant. The
relevant standards are section 3.5 of RFC 1034 (Internet Standard 13), section
2.1 of RFC 1123 (Internet Standard 3, which refers to RFC 952), section 4.1.2
of RFC 821 (Internet Standard 10) and sections 4.1.2 and 4.1.3 of RFC 2821. This
filter will block hosts with underscores in their HELO/EHLO name, those hosts
are not compliant with these standards.
- Happy99 virus filter
- This filter will bounce any message with an X-Spanska: header starting with "yes".
- Papa virus filter
- This filter will bounce any message with an Subject: header starting with
"Fwd: Workbook from all.net and Fred Cohen".
- Bulk Mailer Filter
- This filter checks the headers of messages for the signature of a common bulk mailer program.
- Bulk Mailer2 Filter
- This is another filter that checks the headers of messages for the signature of a
common bulk mailer program.
- Host Name Filter
- This filter checks the SMTP HELO/EHLO name against the one in the STR# resource. This
can be useful for blocking dictionary attacks that always use the same HELO/EHLO host
name, and for blocking spam that always uses your servers IP address as the HELO/EHLO host name.