_I need help figuring out what a Delivery Status Notification (DSN)
bounce message message is saying. Can you help me learn how to
interpret these messages?_
E-mail is exchanged using a protocol called SMTP. The DSN or bounce
message is a report base...
Following are some of the commonly seen SMTP return codes.
211 System status, or system help reply
214 Help message
220 Service ready
221 Service closing transmission channel
421 Service not available,
250 Requested mail action okay, completed
251 U...
Someone tried to send me a message and received "SMTP Error 553
5.1.8... Domain of sender address does not exist". What does this
mean?
In this situation, your mail server has refused the e-mail because it
cannot identify the sender's domain (e.g. e...
_An e-mail I was expecting did was expecting a message and it did not
arrive. When I checked the transmission log I saw "milter" errors
saying "timeout before data read" and "to error state". What is going
on? Is there a problem with my antispam server...
SUMMARY:
Why am I getting a Command Unrecognized: "XXXXXXXX" error? ANSWER:
Most likely a Cisco ASA is performing "inspect esmtp" or "inspect
smtp" on incoming e-mail traffic. If the Cisco ASA finds an
objectionable incoming SMTP command, it will re...
SUMMARY:
What is Sender Policy Framework (SPF)? How does it work? How can I
prevent SPF issues? ANSWER:
Message Example:
550-5.1.1 SPF Block: YOUR DNS says [192.168.1.13] can't send
mail(ID:l15I924U002784))
This sort of reject message occurs w...
SUMMARY:
You are receiving errors from your mail client saying "can not read
winmail.dat" or some similar error. You are *not* using a Microsoft
e-mail client. ANSWER:
winmail.dat is a proprietary Microsoft method of encrypting mail.
This file is ge...
This error often occurs when custom scripts are created to send e-mail
notifications, mail blasts, etc. The use of any separator character
other than a comma ',' is not standards compliant. The Internet
Message Format (RFC 2822 [1]) requires lists of e-ma...
E-mail deferral occurs when a message (usually outgoing) cannot be
immediately handed off to the next relay host. It is quite common to
have messages queued as "deferred" as remote mail servers may not be
available for any number of reasons: network tr...
SUMMARY:
Why is Google/GMail/Postini giving a 500 500 5.5.1 Command
Unrecognized: "XXXXXXXX" error? ANSWER:
Google/GMail/Postini returns a "Delivery Status Notification
(Failure)" message with the following text: Delivery to the following
recipient ...