They issue a QUIT after receiving a response to the RCPT TO: (which is what they are checking). I believe postfix will try to set the MAIL FROM: e.g. postmaster@verizon.net. Exim would use a bounce format and leave it blank. Not sure what other MTA's use there.
Check out RFC 2821. I found this part esp interesting to this discussion:
3.10 Mailing Lists and Aliases
An SMTP-capable host SHOULD support both the alias and the list
models of address expansion for multiple delivery. When a message is
delivered or forwarded to each address of an expanded list form, the
return address in the envelope ("MAIL FROM:") MUST be changed to be
the address of a person or other entity who administers the list.
However, in this case, the message header [32] MUST be left
unchanged; in particular, the "From" field of the message header is
unaffected.
This implies that the "person or other entity" is a valid email address that can accept mail and therefore, bounces.
It doesn't send a bounce, but it checks to see if one *could* be sent. It is a common anti-spam measure. If you really want to understand this, try googling for sender verification or sender callout and MTA. The nice thing is that you don't need to understand it, but your university mail admins should and my previous desciption should be more than adequate to put them on the right track.
"Sender cannot be verified, which is the cause of their mail issue. NOTE: 451... Requested mail action not taken: mailbox unavailable. Whitelisting will not help. They will need to correct the config on their mail server."
It does makes sense. You either have poor mail admins or it does work (and makes sense) and VZ is smokin something.
What that says is that VZ tried to send a message (probably a bounce) to the envelope sender and received a 451 error (mailbox unavailable) from the university server. If the sender won't accept a bounce for the message, then something is likely misconfigured. Have your school create a mailbox for the sender address even if it sends everything to/dev/null.
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I would have to double-check to be sure, but I believe that is the case. In the SMTP conversation:
EHLO domain.com
MAIL FROM: <sender@domain.com>
RCPT TO: <recipient@someplace.com>
gets changed to the listmanager entity, but
DATA
From: Some Guy <sender@domain.com>
To: Some Gal <recipient@someplace.com>
Subject: Hi
Hi
.
QUIT
remains the same.
They issue a QUIT after receiving a response to the RCPT TO: (which is what they are checking). I believe postfix will try to set the MAIL FROM: e.g. postmaster@verizon.net. Exim would use a bounce format and leave it blank. Not sure what other MTA's use there.
Check out RFC 2821. I found this part esp interesting to this discussion:
3.10 Mailing Lists and Aliases
An SMTP-capable host SHOULD support both the alias and the list
models of address expansion for multiple delivery. When a message is
delivered or forwarded to each address of an expanded list form, the
return address in the envelope ("MAIL FROM:") MUST be changed to be
the address of a person or other entity who administers the list.
However, in this case, the message header [32] MUST be left
unchanged; in particular, the "From" field of the message header is
unaffected.
This implies that the "person or other entity" is a valid email address that can accept mail and therefore, bounces.
It doesn't send a bounce, but it checks to see if one *could* be sent. It is a common anti-spam measure. If you really want to understand this, try googling for sender verification or sender callout and MTA. The nice thing is that you don't need to understand it, but your university mail admins should and my previous desciption should be more than adequate to put them on the right track.
"Sender cannot be verified, which is the cause of their mail issue. NOTE: 451 ... Requested mail action not taken: mailbox unavailable. Whitelisting will not help. They will need to correct the config on their mail server."
/dev/null.
It does makes sense. You either have poor mail admins or it does work (and makes sense) and VZ is smokin something.
What that says is that VZ tried to send a message (probably a bounce) to the envelope sender and received a 451 error (mailbox unavailable) from the university server. If the sender won't accept a bounce for the message, then something is likely misconfigured. Have your school create a mailbox for the sender address even if it sends everything to