Date: Wed, 10 Oct 2001 22:07:58 -0700 From: "Ted Mittelstaedt" <tedm@toybox.placo.com> To: "Jeremy C. Reed" <reed@reedmedia.net>, "Szilveszter Adam" <sziszi@bsd.hu> Cc: <freebsd-advocacy@FreeBSD.ORG> Subject: RE: advocacy/31194: freebsd.org mailing lists - configuration problem? Message-ID: <006301c15212$b17e06c0$1401a8c0@tedm.placo.com> In-Reply-To: <Pine.LNX.4.21.0110101027190.3559-100000@pilchuck.reedmedia.net>
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This is an excellent point. anti-spam rejects should always have error codes starting with a 5 otherwise the sending server requeues and continues to resend indefinitely, burning up your bandwidth. Some people like to 4 them to tarpit the senders, but you need to be behind a DS-3 or your going to burn down your own house. Ted Mittelstaedt tedm@toybox.placo.com Author of: The FreeBSD Corporate Networker's Guide Book website: http://www.freebsd-corp-net-guide.com >-----Original Message----- >From: owner-freebsd-advocacy@FreeBSD.ORG >[mailto:owner-freebsd-advocacy@FreeBSD.ORG]On Behalf Of Jeremy C. Reed >Sent: Wednesday, October 10, 2001 10:55 AM >To: Szilveszter Adam >Cc: freebsd-advocacy@FreeBSD.ORG >Subject: Re: advocacy/31194: freebsd.org mailing lists - configuration >problem? > > >(Not sent to gnats. I understand this is closed, but I do have a few >comments.) > >On Wed, 10 Oct 2001, Szilveszter Adam wrote: > >> The symptom is that the message is rejected with a transitional error of: >> >> Helo command rejected; host not found and with an error code of 450 (I >> think) > >Yes. It is a 450. > > 220 hub.freebsd.org ESMTP Postfix (Postfix Rules!) > helo pilchuck > 250 hub.freebsd.org > mail from: <reed@reedmedia.net> > 250 Ok > rcpt to: <thisshouldbounce@freebsd.org> > 450 <pilchuck>: Helo command rejected: Host not found > quit > 221 Bye > >Just for your information, this is suggested in RFC 2821 (which obsoletes >821): > > The argument field contains the fully-qualified domain name > of the SMTP client if one is available. In situations in which the SMTP > client system does not have a meaningful domain name (e.g., when its > address is dynamically allocated and no reverse mapping record is > available), the client SHOULD send an address literal ... > >If the problem had to do with reverse lookups that didn't match up, then: > > An SMTP server MAY verify that the domain name parameter in the EHLO > command actually corresponds to the IP address of the client. However, > the server MUST NOT refuse to accept a message for this reason if the > verification fails: the information about verification failure is for > logging and tracing only. > >> Watch the transitory error messages come back for a few a days until >> your SMTP server gives up and the message fails. >... >> Also, leaving a message in limbo for several days is not exactly a >> great idea when you know that you won't accept it ever. > >But I don't think this part of your comments were answered. > >It seems like the mail server should not return a temporary error. >I am not sure why the 450 "Helo command rejected: Host not found" occured >after the "RCPT TO". > >I believe it should occur directly at the HELO (OR EHLO) with a permanent >error, i.e.: > > helo pilchuck > 500 <pilchuck>: Helo command rejected: Host not found > >(The RFC says: "If the EHLO command is not acceptable to the SMTP server, >501, 500, or 502 failure replies MUST be returned as appropriate.") > > Jeremy C. Reed -- who is thinking about configuring his mail servers to > log and then maybe reject invalid HELOs to try to > stop more spam ... > > >To Unsubscribe: send mail to majordomo@FreeBSD.org >with "unsubscribe freebsd-advocacy" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-advocacy" in the body of the message
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