Re: Undeliverable Interpretation

Good luck with that. A former employer's mail server got stuck on an
anti-spam list because that particular list added a block of 5 class
C's to thier block list because of ONE spammer on a completely
different subnet. Asking to be removed was met with hostile derision
and accusations of supporting spammers. Luckily for us, we were slated
to re-ip our network anyway...we just ended up having to push up the
time schedule a bit.

DJones wrote:
Aaron,

Thanks for the information. I am following yours and Matts' leads to see
what I can find. I have made all attempts I know of to lock down our server
so that we don't get involved in any spam operations. If indeed we are on a
RBL, I'll need to get to the bottom of it and get it resolved asap. Thanks
for the help.
--
Dave Jones


"Aaron" wrote:

550 is the SMTP error code returned by the remote server. The rest of
it is extra information provided by the remote server. In this case,
I'd say that yes, it is rejecting your mail server connection due to a
block list of some sort. There are some pretty paranoid Block Lists
out there that will add large blocks of IP's. You might have gotten
swept up in one of those.

DJones wrote:
I'm running a MS Exch 2003 server and have recently received several notices
from my mail users that they are suddenly unable to send e-mail to a
particular e-mail address external to our network.
Mail to the recipient has not been problematic until a couple of weeks ago
and I've made no changes in Exchange.

I sent a few test emails myself with the same results.
We're receiving an "Undeliverable" message from our Exch 2003 server with
the message content:
"There was a SMTP communication problem with the recipient's email server.
Please contact your system administrator <server.domain.lan #5.5.0
smtp;550-xxx.xxx.xxx.xxx block by ldap:ou-rblmx,dc=worldnet,dc=net>"

I'm trying to understand exactly what the content in the brackets of the
"Undeliverable" message is telling me. I recognize my server, domain and IP
address. What is the #5.5.0 smtp? Simply an error code?
What exactly is the rest of the message saying and how do I address it?
Could this possibly be the result of being placed on an Real-Time Blacklist?

Your feedback is much appreciated!
--
Dave Jones



.

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