multihomed server, 2 NICs, not forwarding packets

[Andrew Allen]

set-up NT 4/sp 6 multihomed server with two 3com NICs and IP enabled will
not allow a client on the internal network (card) ping a router on the
external
network through the multihomed server. External NIC gateway set to router's
IP and internal NIC gateway is blank.

Both on separate Subnets.

Any help?

[John R Buchan]

It's not enough to simply place a router between 2 subnets. You also need
to tell the clients and other routers how to make use of the router. In
your setup, you might typically:

1) Set the Default Gateway (DG) of the client to the local IP of the
NT Router.

2) Add a static route to the router to tell it that the 'other'
subnet is available through the local IP of the NT Router.

For example (all masks 255.255.255.0):

NT router:
NIC1: 192.168.1.1
NIC2: 192.168.2.1
DG: 192.168.2.2

Clients on 192.168.1.0:
IP: 192.168.1.2 - 192.168.1.254
DG: 192.168.1.1

Router1
NIC1: 192.168.2.2
NIC2: ....... (not relevant)
Static route:
Destination: 192.168.1.0
Mask: 255.255.255.0
Gateway: 192.168.2.1

Of course, if there are clients and/or other routers beyond Router1, you
will need to give them routing information to allow them to reach
192.168.1.0, as well.

--
Note, I seldom respond to email questions. Please keep discussions in
the news group, so everyone can benefit from them (including me <g>).
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
For direct access to all MS newsgroups: news://msnews.microsoft.com/

John R Buchan Independent Consultant Orlando, Florida USA
MCSE -++- MVP ...................... j.buchan(at)worldnet.att.net

[John S. Giltner, Jr.]

The router on the external network must have a route table entry pointing to the external NIC of the multihomed server to get back to the internal network.  That is

internal network    10.1.1.0    255.255.255.0
external network    10.1.2.0   255.255.255.0

Multihomed server internal NIC 10.1.1.1
                            external NIC 10.1.2.1

The extrnal router must have a route statment for subnet 10.1.1.0 255.255.255.0 pointing to IP address 10.1.2.1 as the router.

Andrew Allen wrote:

set-up NT 4/sp 6 multihomed server with two 3com NICs and IP enabled will
not allow a client on the internal network (card) ping a router on the
external
network through the multihomed server. External NIC gateway set to router's
IP and internal NIC gateway is blank.

Both on separate Subnets.

Any help?