For some reason I can't seem to send any email to gmail accounts. The google mail servers keep telling me:
451 4.5.0 SMTP protocol violation see RFC 2821
The MTS is standard postfix and I've tried it from a couple different machines which otherwise don't have any problems sending mail.
A google search turned up other people with the same problem but no solutions.
Anyone have a clue what the problem is?
Just in case someone stumbles on this thread; I never did do anything to solve this problem but it just seemed to go away on it's own.
I suspect this is a form of Google greylisting. Once google gets to know you a bit better it stops delaying your mail.
On 2008-11-12 16:55, John Lange wrote:
Just in case someone stumbles on this thread; I never did do anything to solve this problem but it just seemed to go away on it's own.
I suspect this is a form of Google greylisting. Once google gets to know you a bit better it stops delaying your mail.
...
451 4.5.0 SMTP protocol violation see RFC 2821
Usually, an error message like that would suggest something is messed up in the MTA configuration at one end or the other. Did you bother to check this site for likely possibilities?...
http://www.rfc-ignorant.org/rfcs/rfc2821.php
On Wed, Nov 12, 2008 at 5:16 PM, Gilbert E. Detillieux < gedetil@cs.umanitoba.ca> wrote:
451 4.5.0 SMTP protocol violation see RFC 2821
Usually, an error message like that would suggest something is messed up in the MTA configuration at one end or the other. Did you bother to check this site for likely possibilities?...
Which one of the 79 pages do you suggest he starts with, Gilbert?
While you're mulling that over, I'll suggest something more helpful:
http://forums.devshed.com/mail-server-help-111/gmail-responds-451-4-5-0-smtp...
Google's the one at fault here, the thread has a workaround from the postfix mailing list, and seems to have fixed the problem permanently.
Sean
I had the suggestion earlier that it could be pipelining related, and saw a similar thread but...
Assuming that is the problem then that error message really doesn't make sense since Pipelining is an RFC 2821 (and related) compliant feature.
Further, I don't feel I should have to disable a legitimate SMTP feature just to get along with GMail. Especially since it would actually be GMail that would be the one violating the RFC (unless there is an as yet unreported Postfix bug which is highly unlikely).
And finally, even though the thread reports that after disabling pipelining (I assume that is what that postfix option effectively does) things started working. However, I did nothing and things started working so my guess is that the fix is required.
The error hasn't happened again since at least Nov 9th (last time the log was rotated) and all the mail did finally get through though it was much delayed.
My gut feeling is that it is some kind of GMail spam reduction related to pipelining but after you persist enough GMail "learns" that you are not an "evil pipeliner" but are using that feature legitimately and starts letting mail through on the first try.
- John Lange www.johnlange.ca
On Wed, 2008-11-12 at 17:53 -0600, Sean Walberg wrote:
On Wed, Nov 12, 2008 at 5:16 PM, Gilbert E. Detillieux gedetil@cs.umanitoba.ca wrote:
> 451 4.5.0 SMTP protocol violation see RFC 2821 Usually, an error message like that would suggest something is messed up in the MTA configuration at one end or the other. Did you bother to check this site for likely possibilities?... http://www.rfc-ignorant.org/rfcs/rfc2821.phpWhich one of the 79 pages do you suggest he starts with, Gilbert?
While you're mulling that over, I'll suggest something more helpful:
http://forums.devshed.com/mail-server-help-111/gmail-responds-451-4-5-0-smtp...
Google's the one at fault here, the thread has a workaround from the postfix mailing list, and seems to have fixed the problem permanently.
Sean
-- Sean Walberg sean@ertw.com http://ertw.com/
On 2008-11-12 17:53, Sean Walberg wrote:
On Wed, Nov 12, 2008 at 5:16 PM, Gilbert E. Detillieux <gedetil@cs.umanitoba.ca mailto:gedetil@cs.umanitoba.ca> wrote:
> 451 4.5.0 SMTP protocol violation see RFC 2821 Usually, an error message like that would suggest something is messed up in the MTA configuration at one end or the other. Did you bother to check this site for likely possibilities?... http://www.rfc-ignorant.org/rfcs/rfc2821.phpWhich one of the 79 pages do you suggest he starts with, Gilbert?
Actually, I was thinking of the 5 or 6 colour-highlighted passages within the page, corresponding to the conveniently-indexed sections listed right at the top of the page, which point to some of the more likely issues to be encountered with misconfigured MTA's.
But it looks like none of those were particularly relevant in this case...
While you're mulling that over, I'll suggest something more helpful:
http://forums.devshed.com/mail-server-help-111/gmail-responds-451-4-5-0-smtp...
Google's the one at fault here, the thread has a workaround from the postfix mailing list, and seems to have fixed the problem permanently.
See also: http://www.spamresource.com/2008/11/gmail-tempfailing.html
While browsing this site today, for totally different information, I came across that entry. Looks like sites running "an MTA that utilizes pipelining aggressively" (Postfix is a likely one) are running into this. John, if the problem went away without you changing anything at your end, it's possible Gmail tweaked something in response to complaints from others.
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Gilbert E. Detillieux -
John Lange -
Sean Walberg