topic Re: transparent routing in Operating System - HP-UX

transparent routing

U.SivaKumar_2 — Fri, 20 Sep 2002 04:41:59 GMT

Hi,
Assume i have a setup like this.

|PC|-------------| HP-UX box |-----------|PC|
90.0.0.0 90.0.0.0
255.0.0.0 255.0.0.0
net A net B

net A and net B are physically isolated.

Now my question is , Can I ping from one PC to
another ?.

regards,
U.SivaKumar

Re: transparent routing

Edgar Matzinger — Fri, 20 Sep 2002 09:30:46 GMT

Hi,

you can setup gated on the HP box and a default route on each PC to the HP box.

HTH, cu l8r, Edgar.

Re: transparent routing

W.C. Epperson — Fri, 20 Sep 2002 15:57:29 GMT

I don't think gated is necessary--that just determines whether HP-UX _advertises_ itself as a router. Since time immemorial a multi-homed HP-UX server will act as a router unless the function is specifically turned off. You used to have to hack the kernel with adb, but can now turn it off in /etc/rc.config.d/nddconf:
TRANSPORT_NAME[8]=ip
NDD_NAME[8]=ip_forwarding
NDD_VALUE[8]=0

Unless it has been turned off, the HP-UX box in your diagram would try to forward packets based on its own routing tables if one of the PCs used it as a router. But since you seem to have the same network number on both sides of the HP-UX box, I don't think it could know what to do.

Re: transparent routing

Ray Brewer — Fri, 20 Sep 2002 16:08:41 GMT

Assuming ip_forwarding is on on the HP box, yes you should be able to ping from one PC to the other as long as each PC has a route defining the HP box at the gateway to use to get to the other network.
Even if you turn ip_forwarding on the HP box off you can still set up the routing on the HP box to make this possible. Turning ip_forwarding off basically turns the HP box into a simple firewall.

Ray

Re: transparent routing

Anil C. Sedha — Fri, 20 Sep 2002 20:13:59 GMT

Hi Siva,

If there are routes defined on the HP server to both the boxes you will be able to do a ping.

By this i mean, that the route should be going through the hp box for PC1 to PC2.

On PC1
route add net pc2ipaddress netmask *.*.*.* hpuxipaddress 0

This will enable PC1 to use IP address of HP UX box to use as a gateway.

Then do the similar thing in PC2 providing Ip address of pc1 instead of pc2 in the route add command.

Regards,
Anil

Re: transparent routing

U.SivaKumar_2 — Mon, 23 Sep 2002 05:53:10 GMT

Well , If iam connecting from
HP-UX server , there can be some conflict.

But iam not going to use the server. then in the both PCs
I give default gateway as respective HP server's interfaces.

It should work now ?

regards,
U.SivaKumar