Our company has a Star shaped WAN setup via draytek routers from a central office to 5 satellite sites. We have had a problem with the broadband at the central office (two lines from two ISPs, one of which has gone down) which, for a period of time means that we cannot send SMTP from our exchange server out through the central office broadband to our ISP (of the broadband that has failed). if we relay all packets destined for the internet via a VPN to another office and out, the SMTP relay works. This has the issue of saturating that VPN link.
I have Exchange 2003 running on server 2003 in the central site and server 2008 at the satelite site.
My question is, can we force SMTP packets to go out via the VPN to a satelite office and thence to the internet whilst having all other packerts from the central office going out directly to the internet from the local broadband connetion?