On Fri, Apr 27, 2012 at 11:36:16AM +0100, Ron Yorston wrote: > According to RFC 5321 the argument to HELO "contains the fully-qualified > domain name of the SMTP client" or its IP address if no FQDN is available. > BusyBox sendmail uses the NIS domain name instead which, in many cases, > is likely to be the default "(none)". Despite this BusyBox sendmail works > because, per RFC 1123, the server "MUST NOT refuse to accept a message, > even if the sender's HELO command fails verification".
My mailserver ignores this MUST, because ignoring it and rejecting such behavior blocks 75-90% of spam before it even gets to the filter/analysis stage, and doesn't block any mail from a *conformant* sender. I expect others might do the same, or at least add a very high spam probability score to such broken senders. Thus, fixing busybox sendmail in this regard should be considered important in my opinion. Rich _______________________________________________ busybox mailing list [email protected] http://lists.busybox.net/mailman/listinfo/busybox
