(only sysop, init.bcm, only Linux/Win32, option INETMAILGATE in config.h)
(default: off)

If <CALL> is defined and an email is received via SMTP interface, following
will happen:

- the sender email address will be converted in the lokal adress <CALL>
  (e.g. meier@darc.de -> DB0ABC if "internetmailgate db0abc" is defined)
- the original sender email address will be added to the subject of the mail
  (e.g. "meier@darc.de - blabla" will be the subject)
- the receiver email address will be truncated to the receiver callsign
  (e.g. db1abc@db0abc.de -> DB1ABC)

Hint: The Home-BBS of <CALL> should be the own mailbox!