NT Router Configuration Problems

  • Thread starter Thread starter Leonard Hopkins
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Leonard Hopkins

I have an NT4 SP6 box that I want to setup as a router in a small LAN for
testing. The problem I have is that I am unable to get out to the Internet
once the second NIC is installed. The system is an HP NetServer e50

The first NIC is a HP NetServer 10/100TX PCI card running at 100 Mbs/Full
Duplex. It's IP address is 10.0.2.250/24 - default gateway 10.0.2.254. I
have no problems accessing the internet from the default gateway at
10.0.2.254.

The second NIC is an Intel PRO 10/100 @ 100 Mbs/Full Duplex. It's IP address
is 10.0.1.254/24 - with the same default gateway.

I am confused as to what to set the default gateway to on both NIC's. Should
it be the Internet Gateway of 10.0.2.254 or should the default gateway be
the NICs own IP address? I have tried both ways and a combination of them
and still can't access the Internet from the system.
 
The problem here is that NT doesn't know how to route traffic between the
NICs unless you specifically instruct it. The default gateway is correct,
indeed it *should* use the same default gateway regardless of subnet. But
you've provided no further guidance, you've merely installed two NICs, and
thus two subnets, but when traffic comes in on one NIC, well, there are no
miracles performed here. An address comes in on NIC #1 (in this case, the
default gateway) targeted at an address that YOU know can be found on the
subnet associated w/ NIC #2, but NT doesn't know it! It just gets it, and
throws up its hands.

So let's tell it...

Go to the HP NetServer, go to a command line and execute the following:

add route 10.0.2.0 mask 255.255.255.0 10.0.2.250

What this says is, "to find any address on the 10.0.2.x subnet (which
includes the default gateway), just drop it on the 10.0.2.250 NIC, it'll
take care of it from there"

Or, if you want to restrict the traffic *just* to the default gateway, add
this route:

add route 10.0.2.254 mask 255.255.255.0 10.0.2.250

What this says is, "to find the specific address 10.0.2.254 (the default
gateway), just drop it on the the 10.0.2.250 NIC, it'll take care of it from
there"

That's it. Yeah, you'd THINK it would know this, that you wouldn't have to
tell it what seems obvious, but that's not the case. Now it knows. Of
course, make sure IP forwarding is enabled too! Or else, it won't work
either.

HTH

Jim
 
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