More SMTP errors

I'll eventually start putting up more information that I have regarding the various smtp errors that I seem to run into on a daily basis. It's never until someone's email server starts throwing up error messages do you really get that full realization of what the hell is going on with the server or your mail.

I hate spam and I hate viruses so coming up with a layered approach to prevent the incoming and outgoing crap is much needed. Once your email reputation goes down the tubes tempers will rise just as quickly.

Your message did not reach some or all of the intended recipients

Working with different customers we always seem to run into the same type issues over and over. In a previous post I talked about the 4.4.7 Could Not Deliver Message error, this time has to do with not having permission to send.

Your message did not reach some or all of the intended recipients. Subject: test Sent: 10/2/2007 8:33 AM

The following recipient(s) could not be reached:

ruth@testdomain.com on 10/4/2007 8:58 AM
You do not have permission to send to this recipient. For assistance, contact your system administrator.
... Access temporarily denied. IP name lookup failed [196.25.11.101]>

The message failed going over to Ruth at testdomain coming from testo at 196.25.11.101. For this customer we actually found out that it was again a combination of missing reverse DNS records and possible blacklisting. You can do a Reverse DNS lookup on www.dnsstuff.com or on www.openrbl.org using either the CGI or JS client.

If you have Exchange 2003 at the site you are trying to research this for then another great tool to use would be SMTPDIAG. You can download it from here and read an article on how to use it here. It really helps with testing so you’re not sending 50 messages and then having to wait for them to bounce back or error out eventually.