Postfix Overview - Introduction - SCN Research

Postfix Configuration - UCE Controls
permit
reject
reject_unauth_pipelining
See generic restrictions.
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Require HELO (EHLO) command
The smtpd_helo_required parameter determines if clients must send a HELO (or EHLO) command at the
beginning of an SMTP session. Requiring this will stop some UCE software.
Default:
smtpd_helo_required = no
By default, the Postfix SMTP server does not require the use of HELO (EHLO).
Syntax:
Example:
Specify yes or no.
smtpd_helo_required = yes
HELO (EHLO) hostname restrictions
The smtpd_helo_restrictions parameter restricts what hostnames clients may send with the HELO (EHLO)
command. Some UCE software can be stopped by being strict here.
Default:
smtpd_helo_restrictions =
By default, the Postfix SMTP server accepts any garbage in the HELO (EHLO) command. There
is a lot of broken or misconfigured software on the Internet.
Syntax:
Specify a list of zero or more restrictions, separated by whitespace or commas. Restrictions are
applied in the order as specified; the first restriction that matches wins.
In addition to restrictions that are specific to HELO (EHLO) command parameters, you can also specify
restrictions based on the client hostname or network address.
Example:
smtpd_helo_restrictions = permit_mynetworks, reject_invalid_hostname
Restrictions:
reject_invalid_hostname
Reject the request when the client HELO or EHLO parameter has a bad hostname syntax.
The invalid_hostname_reject_code specifies the response code to rejected requests (default: 501).
permit_naked_ip_address
Permit the request when the client HELO (EHLO) command contains a naked IP address
without the enclosing [] brackets that the RFC requires. Unfortunately, some popular PC mail
http://www.porcupine.org/postfix-mirror/uce.html
6/26/01