July 30, 2011 Roberto Puzzanghera0 comments
Last week me and a couple of friends of this blog dealed with a trouble which engaged us for many hours, until Stéphane Cottin sent me this patch after 3 minutes from my request!
Create a sieve rule which rejects the incoming messages for vacation or whatelse and you will see that it will bounce back because of a syntax error in the sender address. And if you look to the smtp conversation this is what you would see:
@400000004e2e94a60345ab5c 2604 < MAIL FROM:<"<>"@domain.xy> @400000004e2e94a603496864 CHKUSER rejected sender: from <<>@domain.xy::> remote 553 5.1.7 sorry, mailbox syntax not allowed (chkuser)
The response is from
chkuser because it was a test with my own
qmail server, but a similar failure would return from other mail servers.
The reason is in the
qmail-inject man page:
Default host name. Default: me, if that is supplied; otherwise the literal name defaulthost, which is probably not what you want. qmail-inject adds this name to any address without a host name.
Usually the null sender
<> belongs to system's messages, but in this case it has been rewrited with
<>@domain.xy and this is causing the rejection.
As you can see, the patch gets
qmail-inject to avoid the rewrite of the null sender:
2011-07-26 15:22:10.244210500 8001 < MAIL FROM:<> 2011-07-26 15:22:10.244465500 CHKUSER accepted sender: from remote <domain.xy:unknown:123,456.789.123> rcpt <> : accepted null sender always 2011-07-26 15:22:10.245288500 8001 > 250 ok
apache clamav dkim dovecot ezmlm fail2ban hacks lamp letsencrypt linux linux-vserver lxc mariadb mediawiki mozilla mysql openboard owncloud patches php proftpd qmail qmailadmin rbl roundcube rsync sieve simscan slackware spamassassin spf ssh ssl surbl tcprules tex ucspi-tcp vpopmail vqadmin