Multi-Homed Gateway Computers
A multi-homed computer is one that has more than one network card and therefore more than one IP address. By default, WorkgroupMail will listen for POP3 and SMTP connections on all IP
interfaces. For example, if the gateway computer has an IP address of 45.54.143.245 and 192.168.0.1, either of these IP addresses may be specified as the SMTP and POP3 server in the local mail
client. However, if one of these interfaces is exposed to the Internet, you may not wish to make the local SMTP and POP3 server available on the external interface, since, unless
protected by a firewall, anyone could use the SMTP server to send their own e-mail. For this reason, WorkgroupMail lets you specify the interface(s) on which the local SMTP and POP3 servers will be
available.
If mail is received using SMTP then if the gateway machine is multi-homed, you may also wish to specify which interface will be used for listening for incoming SMTP connections.
You can specify the interface used for local clients by selecting either [All Available Interfaces] or a specific interface from the top drop down list.
You can specify the interface used for remote servers to send mail to WorkgroupMail using SMTP by selecting either [All Available Interfaces] or a specific interface from the bottom drop
down list.