Routing based on packet source?

[Workgroups]

Is RAS able to implement routing logic that could emulate this logical
scenario?

If your destination is A Then
If you're coming from Subnet 1 Then
Goto Gateway 1 via Interface 1
Else
Goto Gateway 2 via Interface 2
End If
End If

Or to put it another way, I wish I had these theoretical static routes:

Source = 172.16.2.0/24
Dest = 0.0.0.0/24
Gateway = [whatever]
Interface = [WAN NIC A]

Source = 0.0.0.0/24
Dest = 0.0.0.0/24
Gateway = [whatever]
Interface = [WAN NIC B]

The gory details are that I have both a T1 and a DSL line here, and both are
connected to a tri-nic'd W2K3 server that is running both RAS and IIS. Back
when I only had the DSL to deal with, giving my LAN internet access was easy
because there was only 1 WAN nic (the DSL), and the "last resort" 0.0.0.0/24
being routed through it was the clear & obvious choice.

Now that the T1 has been added, this W2K3 box now has 2 WAN nics facing the
internet, and IIS now listens on the T1 for www & ftp requests. However, I
want keep my LAN surfers *off* the T1 bandwidth, so I kept the DSL line
thinking I could route "last resort" over the DSL interface where the packet
originated from the LAN (keeping my internal internet surfers off the T1
bandwidth); and any packets that originated from the WAN (i.e. they
originated from the internet over the T1 line for IIS) would choose the T1
as last resort (so that they go back where they came from).

But so far I'm left choosing one or the other for 0.0.0.0/24, and in order
for IIS to work that means routing it (and all my LAN people) out through
the T1.

 

[Bill Grant]

No. There is no way to route traffic differently based on where it came
from.

You can specify more than one default gateway, but only one will be
active.