SMTP Connector not sending to some domains after ISP and Static IP Change
I have been racking my brain on this issue for the past couple days.
companyA.com recently changed ISPs from Comcast to TDS. With that got a new IP Address.
DNS registrar is Godaddy.
The server is a Small Business Server 2003, with Exchange 2003. Hosting out own email.
Since the change was made users have been unable to send email to 7 very different domains (so far). I go to the exchange server queue and see the emails sitting there with the SMTP protocol error message. And the users get a NDR email. The most descriptive one was a #4.4.7 error.
Heres what i have checked:
Reverse DNS is correct
SMTP Banner Correct
External IPs removed from the banner area.
Ran Exchange Best practices and made some of the changes it suggested.
Ran the Connection and email wizard in SBS
And much more.
Couple things that may be causing issues that i can see:
the path to the internet is as follows:
Server1 -----> SonicWall router/firewall -----> Cisco router for the T1
192.x.x.x x.x.x.238 x.x.x.237
Should the reverse dns be pointing to the 238 or the 237 address?
Should i be pointing my mail.companyA.com address to the 238 or 237 address.
Any help would be greatly appreciated.