topic question on default gateway in Operating System - HP-UX

question on default gateway

Jeganathan Venkitasamy — Mon, 12 Nov 2001 18:46:35 GMT

Hi all,

Can we configure more than one default gateway in HP-UX 11.0? Reason for this question is that we would like to re-route all outbound traffic network to a stand-by router, default gateway fails.
Is it possible in HP-UX 11.0 to have more than one default gateway?

Thanks & regards,
Jegi
NBC, New York

Re: question on default gateway

harry d brown jr — Mon, 12 Nov 2001 18:51:52 GMT

NO, not without mcsg.

live free or die
harry

Re: question on default gateway

Roger Baptiste — Mon, 12 Nov 2001 18:55:01 GMT

hi,

the word default itself implies there can be only one default to fall back upon ;-)

You can have more than one
gateway for a system , each
one for different subnets.But there can be only one default gateway, which is used as a default when there is no other gateway set for that subnet.

raj

Re: question on default gateway

G. Vrijhoeven — Mon, 12 Nov 2001 18:56:10 GMT

Hi,

look at this URL

http://forums.itrc.hp.com/cm/QuestionAnswer/1,11866,0x775f46ff9277d511abcd0090277a778c,00.html

Gideon

Re: question on default gateway

Sanjay_6 — Tue, 13 Nov 2001 03:46:24 GMT

Hi Jegi,

This link is worth checking,

http://us-support.external.hp.com/cki/bin/doc.pl/sid=3f999570120ed959c6/screen=ckiDisplayDocument?docId=200000048194519

Hope this helps.

Regds

Re: question on default gateway

Manoj Kumar Sarangi — Tue, 13 Nov 2001 09:04:20 GMT

Yes you can have more than one default gateway. But it route count should be one.
If you have two IP addresses on a system, 192.168.10.1/24
192.168.9.1/24 and gateways as 192.168.9.1 and 192.168.10.1 , you can put both gateways as default. You can put this in /etc/rc.config.d/netconf or you can add them via command line :

route add default 192.168.9.1 1
and
route add default 192.168.10.1 1

This should work..

Manoj

Re: question on default gateway

Volker Borowski — Tue, 13 Nov 2001 09:43:02 GMT

Well,

actually there are solutions for this as proposed here

http://deesse.univ-lemans.fr:8003/Connected/RFC/1122/57.html

but not every OS behaves like this.
On MS-Win you need to activate RIP on a client with two default gateways, but I never did a real test for this on HPUX.

Volker

Re: question on default gateway

Duncan Edmonstone — Tue, 13 Nov 2001 10:01:11 GMT

I've seen this work, after a fashion. The problem usually is that all the other devices that communicate with your server through a router must also have the ability to switch to another router, and you must accept that you will suffer some form of network outage while the routing protocols remove the dead router.

In the implementation I saw, the two gateays were both assigned as root, but with the secondary gateway assigned a larger hop count (2 instead of 1). That way the primary gateway was always used until failure was detected by the dead gateway detection, and then traffic was redirected to the seondary gateway.

You may want to tune down the dead gateway detection from the default of three minutes - use the ndd command to change the ip_ire_gw_probe_interval parameter.

Re: question on default gateway

Christopher Caldwell — Tue, 13 Nov 2001 14:55:40 GMT

You can add two default routes, but it probably won't work the way you want. The last default route wins. I suppose the first default route won't take over unless the second one goes away (interface down or removed because the gate no longer exists from an ip perspective).

You could run gated to get the HP to behave more like a router. The HP would get routes injected from somewhere (probably a router) using (probably) OSPF, BGP, or RIP.

OTOH, you could buy a router (which will work with multiple default routes) and make sure that the HP server is redundantly connected to the router (use MC/Service Guard) or your ethernet gear (switches/hubs), obviating the need for multiple default routes on the HP.

Re: question on default gateway

harry d brown jr — Tue, 13 Nov 2001 15:05:37 GMT

Maybe you want to look into gated, but I'm not sure it can work it.

live free or die
harry