SMTP Virtual Server vs. SMTP Connector
1. SMTP virtual server is the protocol stack that actually does the work - sending/receiving SMTP emails. SMTP virtual server alone gives you ability to send/receive Internet emails.
2. SMTP Connector is built on the top of virtual server and provides you more control - such as dispatching emails to different domains to different routes, applying different restrictions, etc.
3. SMTP virtual server only sends/receives emails to/from the IP address it is bound.
4. As for DNS, either specify external DNS servers on SMTP virtual servers or specify forwarder on DNS server that Exchange server uses.
5. The benefits of SMTP Connector are 1) ease of administration; 2) to simplify troubleshooting when issue surfaces.
6. You can either have your SMTP connector delivery the emails directly (given that the connector is able to resolve external domain names - using one of 2 settings in item 4 )
- or -
You can have your SMTP connector forward all emails to a smart host. Although you can specify a smart host on an virtual server, it’s better to set it on the connector. The smart host setting on the connector overrides any smart hosts on the virtual server.