Postmaster@domain.com messages

[EST7745]

I have a handful of domains that show up in my exchange queue that have messages that will not send. They all have some sort of error message like the following:

"The remote server did not respond to a connection attempt."
"Unable to bind to the destination server in DNS"
"The connection was dropped due to an SMTP protocol event sink."

The interesting thing is that almost all the messages are from "postmaster." What exactly does this mean?

 

[EST7745]

I've also noticed that most of the outbound mail that is receiving these errors are to bizzare domain names like TPNET.DL, MAIL.HQ.COM.AR etc etc.

 

[nsantin]

These are usually NDRs for invalid addressed SPAM messages.

Spammers will send a message with an invalid return address and when an NDR is sent it is rejected because the reply too address is invalid.

Only way to get rid of this is to turn off external NDRs in global settings, however that will disable NDRs to valid addresses (i.e. your customers) as well.

 

[EST7745]

I see. Is there any easy way to clear out the queue? I've got nearly 200 of them in there just in the last 2 days.

 

[58sniper]

Eventually, they will time out by themselves.

Pat Richard, MCSE MCSA:Messaging CNA MVP
Want to know how email works? Read for yourself -

http://www.ietf.org/rfc/rfc2821.txt

 

[technejb]

I have this same issue with tons of NDRs. I do not want to turn them off just in case there is a legitimate email sender that miss-types. Was thinking about turning the Expiration Timeout down to 1 or 2 days instead of 3 days like it is set to now. Maybe that will lessen the shear number of NDRs in the que.

I know a little bit about some stuff and I try to put it to use.

 

[58sniper]

But that will apply to legitimate connection problems, as well.

Enable connection and recipient filtering, and tarpitting. That should reduce the numbers greatly.

Pat Richard, MCSE MCSA:Messaging CNA
Microsoft Exchange MVP
Want to know how email works? Read for yourself -

http://www.ietf.org/rfc/rfc2821.txt