Today I found a interesting problem regarding postscreen and a popular (?) address verification milter in sendmail
>From my logs: Sep 30 15:23:53 mail postfix/postscreen[21955]: NOQUEUE: reject: RCPT from [192.109.31.12]: 550 5.5.1 Protocol error; from=<>, to=<valid.u...@charite.de>, proto=SMTP, helo=<mail.embl-hamburg.de> Sep 30 15:23:53 mail postfix/postscreen[21955]: NOQUEUE: reject: RCPT from [192.109.31.12]: 550 5.5.1 Protocol error; from=<postmas...@embl-hamburg.de>, to=<valid.u...@charite.de>, proto=SMTP, helo=<mail.embl-hamburg.de> The idea of using two different senders is very nice per se, but it seems that the milter is triggering some check within postscreen 192.109.31.12 is running: 220 mail.EMBL-Hamburg.DE ESMTP Sendmail 8.13.8/8.13.8/Debian-2; Thu, 30 Sep 2010 16:06:22 +0200; (No UCE/UBE) logging access from: mail.charite.de(OK)-mail.charite.de [141.42.202.200] I cannot say anything about the milter in use. A prior bug report of mine against "Smart Sendmail Filters" https://sourceforge.net/tracker/?func=detail&aid=2815073&group_id=131540&atid=721356 "The sender address verification sends an HELO *before* the receiving server emits its SMTP banner. Thus, the probe (or the whole server) gets classified as "earlytalker" and (in my case) gets disconnected immediately. The verification probes must adhere to the SMTP protocol, otherwise they're worthless because they're generating false negatives." I have no doubt that the error is NOT in Postfix, but what exactly does the log excerpt mean? Which protocol error exactly is postscreen complaining about? -- Ralf Hildebrandt Geschäftsbereich IT | Abteilung Netzwerk Charité - Universitätsmedizin Berlin Campus Benjamin Franklin Hindenburgdamm 30 | D-12203 Berlin Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962 ralf.hildebra...@charite.de | http://www.charite.de
