You can link VPOP3 to Exchange Server, so that Exchange Server sends outgoing mail through VPOP3 and VPOP3 sends any incoming mail directly to Exchange Server.
You should first of all set up VPOP3 to send and receive Internet email as described in the online help.
As both VPOP3 and Exchange Server are on the same computer, you will need to change the TCP/IP port assignments for the SMTP service in Exchange Server. You should NOT change the SMTP service port in VPOP3 as you cannot change the port which Exchange Server will forward to, but you can change the port which VPOP3 will forward to.
On the Exchange Server computer, edit the file \System32\drivers\etc\services using Notepad.
Change the line which says:
smtp 25/tcp mail
so that it says:
smtp 5025/tcp mail
Then restart Windows NT.
If you have a catch-all email account at your ISP:
Go to the Local Mail → LAN Forwarding → Configuration page in the VPOP3 settings. In this LAN Forwarding configuration box put a line like
where mydomain.com is your registered domain, or the subdomain given to you by your ISP, and 192.168.1.1 is the IP address of the Exchange Server computer.
Also, in the External Mail → In Mail page in the VPOP3 settings, make sure that the Extended Email Routing options main radio button is set to Route According to Detected Recipient.
Alternatively, if you have individual email accounts at your ISP, in the External Mail → In Mail page in the VPOP3 settings for each In Mail setting, set the Extended Email Routing options main radio button to Forward all messages to another LAN mail server using SMTP
Then, in the configuration boxes put the email address on the Exchange Server, and the IP address:port of the Exchange Server SMTP service.
On the Exchange Server Internet Mail Connector Connections tab, in the Message Delivery section, choose Forward all messages to host: and enter the IP address of the VPOP3 computer.
Because both VPOP3 and Exchange Server are mail servers, they may both try to use the same TCP/IP ports which will lead to conflicts if they are both running on the same computer. This happens with port 110 (POP3) and 389 (LDAP). To stop these conflicts, either disable these protocols in the Exchange Server settings, or change the ports assigned to these services in the VPOP3 Local Servers tab.
To set up forwarding of incoming mail from VPOP3 to Exchange Server
Go to the VPOP3 Local Mail tab and press the Edit LAN Forwarding button. In this window put a line like
where mydomain.com is your registered domain, or the subdomain given to you by your ISP, and 192.168.1.1 is the IP address of the Exchange Server computer.
On the Exchange Server Internet Mail Connector Connections tab, in the Message Delivery section, choose Forward all messages to host: and enter the IP address of the VPOP3 computer.