Explicit destination causes implicit destination bounce
Dear all,
I have read http://wiki.list.org/pages/viewpage.action?pageId=4030676 FAQ 1.9 about implicit destination. I am sending directly To: the list with no other recipients. The host_name setting is pumb.org.uk. The conversation I had with the SMTP server is shown below. It still results in an implicit destination error. Can anyone suggest why, please?
I'm in the process of migrating my lists from one server to another. I have not yet updated the MX records for the domain, thus my sending the mail directly to the server rather than using a mail program.
Thanks for the help.
user@workstation:~$ telnet server 25 Trying IP... Connected to server. Escape character is '^]'.
220 server ESMTP Exim 4.71 Fri, 11 Mar 2011 14:43:29 +0000 HELO workstation 250 server Hello workstation [89.16.174.50] MAIL FROM:external@email.address
250 OK RCPT TO:mailman@pumb.org.uk 250 Accepted DATA 354 Enter message, ending with "." on a line by itself Subject:Testing from guinevere 3 This is a message 3 . 250 OK id=1Py3ZU-0003YI-Rz QUIT 221 server closing connection Connection closed by foreign host.
-- Regards,
Ian Gibbs ian@flash.org.uk Mon - Wed: +31 (0) 629 202752 Thu - Sun: +44 (0) 7815 142001
On Fri, 11 Mar 2011, Ian Gibbs wrote:
Dear all,
I have read http://wiki.list.org/pages/viewpage.action?pageId=4030676 FAQ 1.9 about implicit destination. I am sending directly To: the list with no other recipients. The host_name setting is pumb.org.uk. The conversation I had with the SMTP server is shown below. It still results in an implicit destination error. Can anyone suggest why, please?
You have no To: header (or any other headers for that matter). The recipient listed on a RCPT TO: command to the SMTP server (known in the SMTP world as the "envelope recipient") is not the same as a To: header. Since the Mailman list address was not found in the message's non-existent To: or Cc: headers, it is an implicit destination.
To SMTP, headers are part of the message's data. They are completely separate from the SMTP commands that tell an SMTP server what to do with the message (otherwise, BCC could not work. A BCC recipient never appears in the headers (or wouldn't be blind) but the BCC recipient must be in the RCPT TO: SMTP command as how else would the destination server know to deliver it to the BCC recipient).
user@workstation:~$ telnet server 25 Trying IP... Connected to server. Escape character is '^]'. 220 server ESMTP Exim 4.71 Fri, 11 Mar 2011 14:43:29 +0000 HELO workstation 250 server Hello workstation [89.16.174.50] MAIL FROM:external@email.address 250 OK RCPT TO:mailman@pumb.org.uk 250 Accepted DATA 354 Enter message, ending with "." on a line by itself Subject:Testing from guinevere 3 This is a message 3 . 250 OK id=1Py3ZU-0003YI-Rz QUIT 221 server closing connection Connection closed by foreign host.
-- Larry Stone lstone19@stonejongleux.com
Larry Stone wrote:
You have no To: header (or any other headers for that matter).
[...]
DATA 354 Enter message, ending with "." on a line by itself Subject:Testing from guinevere 3 This is a message 3 . 250 OK id=1Py3ZU-0003YI-Rz
Larry's response is correct except for this one detail. Actually, this message has a Subject: header and a non-conformant "This" header and no body. The body must be separated from the headers by an empty line.
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan
On Fri, 11 Mar 2011, Mark Sapiro wrote:
Larry's response is correct except for this one detail. Actually, this message has a Subject: header and a non-conformant "This" header and no body. The body must be separated from the headers by an empty line.
Oops. I looked at the original way too quickly. Thanks, Mark, for correcting my post. The lesson in this is that SMTP, like almost all computer command sets, is very intolerant of even the slightest mistake. It does exactly what you tell it to do and has no idea what you meant when you get it wrong. Using Telnet to test SMTP has its uses (I do it to make sure the anti-spam controls on the commands works since that's hard to do by other means) but unless you are prepared to type everything in painful detail, expect weird results. Mailman is best tested with real messages sent by a proper MUA.
-- Larry Stone lstone19@stonejongleux.com
Thanks to you both. Adding To and From headers solves the issue, and the mail is accepted.
Regards,
Ian Gibbs ian@flash.org.uk Mon - Wed: +31 (0) 629 202752 Thu - Sun: +44 (0) 7815 142001
On 11/03/11 18:26, Larry Stone wrote:
On Fri, 11 Mar 2011, Mark Sapiro wrote:
Larry's response is correct except for this one detail. Actually, this message has a Subject: header and a non-conformant "This" header and no body. The body must be separated from the headers by an empty line.
Oops. I looked at the original way too quickly. Thanks, Mark, for correcting my post. The lesson in this is that SMTP, like almost all computer command sets, is very intolerant of even the slightest mistake. It does exactly what you tell it to do and has no idea what you meant when you get it wrong. Using Telnet to test SMTP has its uses (I do it to make sure the anti-spam controls on the commands works since that's hard to do by other means) but unless you are prepared to type everything in painful detail, expect weird results. Mailman is best tested with real messages sent by a proper MUA.
-- Larry Stone lstone19@stonejongleux.com
Mailman-Users mailing list Mailman-Users@python.org http://mail.python.org/mailman/listinfo/mailman-users Mailman FAQ: http://wiki.list.org/x/AgA3 Security Policy: http://wiki.list.org/x/QIA9 Searchable Archives: http://www.mail-archive.com/mailman-users%40python.org/ Unsubscribe: http://mail.python.org/mailman/options/mailman-users/ian%40flash.org.uk
On Fri, Mar 11, 2011 at 12:26:29PM -0600, Larry Stone wrote:
The lesson in this is that SMTP, like almost all
computer command sets, is very intolerant of even the slightest mistake.
It does exactly what you tell it to do and has no idea what you meant when you get it wrong. Using Telnet to test SMTP has its uses (I do it to make sure the anti-spam controls on the commands works since that's hard to do by other means) but unless you are prepared to type everything in painful detail, expect weird results.
I think this is the part where I mention 'swaks(1)':
http://www.jetmore.org/john/code/swaks/a rather awesome little tool that should be in every mail-admin's toolkit.
Last time I looked, it was packaged for Debian, FreeBSD, and CentOS, without too many packager-introduced-foibles.
-- "You know it cannot have been a good night when you get into a fight with Spider-Man and two cross-dressing men" -- Mark Davies (defence lawyer, regarding 'Cage fighters picked on because they were dressed as women for a stag night')
participants (4)
-
Adam McGreggor -
Ian Gibbs -
Larry Stone -
Mark Sapiro