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Unable to receive email on Exchange server after changing ISP's.


I'm helping a company moving their network/server from one location to another.  They have also switched ISP's.  With the new ISP, they received a new static IP.  They have a Windows SBS with Exchange configured and are behind a Sonicwall firewall.  I have updated the firewall with the new static IP address info.  All computers have access to the internet and can send email but they are not receiving email.  I have contacted the hosting company and they have confirmed the MX record is correct, the same as the new WAN IP from the new ISP.  In midst of this change over, the hosting company had changed the port from I believe it was 587, not positive to 443.  I'm certain this is SSL.  Anyways, I changed the Sonicwall firewall rules to allow any WAN request to go to the internal server's IP addres.  Still not receiving email.  Am I missing something?


1 Solution
Cliff GaliherCommented:
External email is always port 25 unless you were/are using a smarthost.

So use something like MXToolbox to make sure the MX record ACTUALLY got updated and propagated. And to test to make sure port 25 is not blocked by your ISP.
TeddyZ83Author Commented:
I had the host change the port number.  It was set to 443 but this was going to the internal web page.  They changed it to 587 and email is receiving now.
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