Hey Guys,
So, we have a toaster install. vpopmail, mysql etc...
We have about 20,000 email accounts, and recently we have observed a very
strange issue.
Occasionaly, when a customer sends a message from squirrelmail, the get a
553 error. (This probably occurs from outlook as well, we just havan't
received any reports of it yet) The odd thing is, that if they continue to
try to send the message, eventually it goes through. Although we do have a
cluster of 4 mail servers. The problem is not unique to any of the
servers. A server will deny the message. But, 10 minutes later the same
server will accept the same message. We have been able to repeatedly
re-produce the problem using telnet, and the exact same SMTP conversation.
Here is an example smtp conversation I captured yesterday using tcpdump.
220 mail.ispemailserver.com mail1 ESMTP
EHLO webmail.mylifeline.net
250-mail.ispemailserver.com mail1
250-STARTTLS
250-PIPELINING
250-8BITMIME
250-SIZE 10000000
250 AUTH LOGIN PLAIN CRAM-MD5
MAIL FROM:<[EMAIL PROTECTED]>
250 ok
RCPT TO:<[EMAIL PROTECTED]>
553 5.7.1 sorry, that domain isn't in my list of allowed rcpthosts (chkuser)
And here is the same conversation today, but without the 553 error:
220 mail.ispemailserver.com mail1 ESMTP
EHLO webmail.mylifeline.net
250-mail.ispemailserver.com mail1
250-STARTTLS
250-PIPELINING
250-8BITMIME
250-SIZE 10000000
250 AUTH LOGIN PLAIN CRAM-MD5
MAIL FROM:<[EMAIL PROTECTED]>
250 ok
RCPT TO:<[EMAIL PROTECTED]>
250 ok
There are no hints or clues in the logs that I have been able to find.
Joey
--
-Joey
C) 803-409-9969
W) 757-233-0834
