I've been trying to figure out my problem for hours!
I have an existing exchange server that had surfcontrol installed... I removed it and set it up with a Barracuda Spam and Virus Firewall.
SOMEHOW email is coming in just fine... however from outside of our LAN I can't telnet or connect via Outlook. I've had several others try from different connections with the same results.
I have many NAT rules on our Watchguard firewall... I've never had a problem. In fact I can access the I don't understand how it's not allowing a client to send email through. I'm 99.9% sure it's not the firewall causing the issue.
It sends email from other servers just fine!
250 xxxxxxxxx Hello recover.mxtoolbox.com [220.127.116.11], pleased to meet you [55 ms]
MAIL FROM: <email@example.com>
250 Ok [54 ms]
RCPT TO: <firstname.lastname@example.org>
550 No such domain at this location (email@example.com) [69 ms]
221 Bye [55 ms]
I'm stumped! I have done a lot of trial and error with no luck. I can provide a lot more information if someone is willing to help me out. I'm certain it's the Barracuda but I can't figure out what exactly :(