topic Re: Multiple NIC's in Operating System - HP-UX

Multiple NIC's

Michael O'brien_1 — Wed, 02 Apr 2003 11:30:10 GMT

Hi,

I have two network cards in A-Class server they are both on the same network but on different subnets by cutting up the netmask.

lan0 192.168.244.134 netmask 255.255.255.240
lan1 192.168.244.194 netmask 255.255.255.240

Only lan0 has a default router configured 192.168.244.129.

When I try and reach another network ie. 10.102.0.44, the traffic always uses interface lan1, which has no default router configured.
When I run a traceroute the message always says multiple cards configured using lan1

My question is, how do I force traffic to use lan0?

Thanks
mike

Re: Multiple NIC's

Dietmar Konermann — Wed, 02 Apr 2003 13:19:28 GMT

Post your netstat -rn output. Have a look at your default route... is really lan0 listed in the "Interface" column? If not, delete the route and add it again.

Best regards...
Dietmar.

Re: Multiple NIC's

Michael Steele_2 — Wed, 02 Apr 2003 13:43:50 GMT

Load balancing two NIC's is tricky and probably better if you separate the NIC's by two subnets.

However, several users have tried and their succusses have varied. Most are using two default rounters in some manner, or static routes in netconf.

You can use two default gateways in your netconf file, one for each lan, but only the first entered into the routing table will typically be used.

So it's best to have the NIC with the most load assigned to the default gateway.

I've also read where using the "...ip_strong_es_model ..." ndd parameter will allow dual default routers, but the results from users who've implemented this parameter appear inconsistent, based upon the manufacturer of the router and its configuration. Using proxy ARP on the router for instance.

To check ip_strong_es_model current setting use:

ndd -get /dev/ip ip_strong_es_model

To actually set it use:

ndd -set /dev/ip ip_strong_es_model 1

Here is one link about 2 nics being implemented:

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x2cba3a7b3682d611abdb0090277a778c,00.html

Here is another:

http://us-support2.external.hp.com/cki/bin/doc.pl/sid=6aa57e860890b36f79/screen=ckiDisplayDocument?docId=500000000092418