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The bounce will come back either almost immediately, or after
several hours, depending on what has happened:
If there is a technical problem with the server at
the receiving end, there will be an initial
WARNING bounce -- usually within four or five hours
-- announcing the delay and stating that continuing attempts
at delivery will be made for four or five days:
Subject: Warning: could not send message for past 1 day
. . . .
**********************************************
** THIS IS A WARNING MESSAGE ONLY **
** YOU DO NOT NEED TO RESEND YOUR MESSAGE **
**********************************************
The original message was received at date/time
from mailadm@localhost
----- The following addresses had transient non-fatal errors -----
recipient's-address
----- Transcript of session follows -----
recipient's-address... REASON
Warning: message still undelivered after 4 hours
Will keep trying until message is 4 days old
|
Here are a few reasons that might be given:
|
Reason in message
|
Probably cause
|
|
Deferred: Connection timed out with recipient's
host
|
The recipient's mail server is probably down or
overloaded
|
|
451 <xxxxxx@wam.umd.edu>... open
timeout on /mail/xxxxxx/.forward
|
The SENDMAIL program can't deliver mail until it checks
to see if the recipient has a .forward file for
forwarding mail.
Apparently the recipient's file server is down, so the
.forward file can't be checked.
|
If all delivery attempts prove unsuccessful, a final bounce
will arrive announcing the failure:
----- Transcript of session follows -----
recipient's-address... REASON.
Message could not be delivered for 4 days
Message will be deleted from queue
|
If the mail is rejected, a bounce will come
back quickly, often within seconds -- unless the recipient is
on some internal mail system without a direct connection to
the Internet. It will look something like this:
(main part of header)
Subject: Returned mail: REASON
The original message was received at date/time
from sender's-host [sender's-IP-address]
----- The following addresses had permanent fatal errors -----
<recipient's-address>
----- Transcript of session follows -----
(see next section for what follows)
|
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