Question : Unable to send using SMTP

Recently we changed our company name!
With this name change we also changed the email addresses of all users from

[email protected] to [email protected]

I was assigned my new static IP address after an office move today, and have successfully updated the MX & A records with our host Heart Internet. I am able to receieve email no problem.

however if i try to reply, it seems to go out in the cyber space and never actually arrives. When updating the MX & A records i decided not to touch the previous domains settings, instead i have opted to leave this with the default settings set by hear internet allowing me to keep connections to old mail using pop3.

I have also added the new domain to Exchange System Manager, Recipents, recipents policy, email addresses.
I deleted the previous smtp entries, however i did leave our existing .int entry along with the x400 entry.

Can anyone shine some light on how to fix this? our SMTP connector is setup with a wild card * in order allow any domain i believe?

Thank you in advance,

Dearg

Answer : Unable to send using SMTP

Under exchange sytem manager Administrative Group, First Adminstrative Group, Servers, Your Serve Name, Protocols, SMTP, Default SMTP Server (Right Click Properties), Delivery TAB, Advanced Button, Fully-qualified Domain Name.  Enter the FQDN that the world should see for this server ie> smtp.company2.com.  Your DNS provider needs to make an A record for this name pointing to you IP on you firewall.  Have smtp traffic forwarded from the firewall to your exchange box.  A reverse DNS entry will be needed to be entered into your ISPs DNS so you won't get blocked as SPAM.  

Then review this to prevent other from relaying through your exchange box: http://support.microsoft.com/kb/821746

Hope this helps!