Exchange 5.x will deque messages waiting for your domain over a dial-up connection.

To deque messages over a routed connection, you can schedule a batch file:

@echo off                              REM Cause dialup router to connect                              ping <ip_address_of_ISP>                              ping <ip_address_of_ISP>                              if not %ERRORLEVEL% EQU 0 exit                              REM If IMS not started, start it.                              net start MSExchangeIMC                              REM use 3rd party retrieval program or                              REM FINGER or                              REM use the AlwaysUseETRN registry value                              REM stop IMS, if you started it.                              net stop MSExchangeIMC                              exit
If using a single host (multiple hosts are very slow), you can use Regedt32 to navigate to:


On the Edit menu, Add Value name AlwaysUseETRN, a type REG_DWORD value, and set the data to 1.

This will cause IMS to send an ETRN command to all ESMTP hosts it connects to, if they advertise support for ETRN, and are listed in the routing table as configured for IMS.