NIC card problems

[Marty Metras]

We have been using 1 NIC card with an alias for the second IP for a long time. This week end I activated the second NIC and moved it IP to the second card. Now one IP on each card.
Simple procedure?
The second NIC keeps going becak to a Disabled state when you look at in SAM.
I moved the IP back to the Primary card as an alias and thing work fine.
What could I misses? Where are the logs for the Network stuff? Nothing in the systlo tat I can see.
Can you help?
Marty

[Patrick Wallek]

Are both IP addresses in the same subnet? If so, then 2 NIC's with IP addresses in the same subnet is not supported.

[Marty Metras]

Patrick,
Are you sayng I can not have 2 NIC cards on the same subnet?
Like 192.168.1.1/255.255.255.0 lan0
and 192.168.1.2/255.255.255.0 lan1
Wow? I did not know that!
I have been doing this with on lan0 and lan0.1 for years.(same card)
This is an HP 9000 rp7400.
Are you sure?
Marty

[Ashwani Kashyap]

Yes you cannot have 2 active NIC cards in the same subnet .

What you have is 2 IP's bound to the same NIC card in the same subnet .

lan0 and lan0:1 is the same NIC card (lan0 ) but two IP's , one bound two lan0 another to lan0:1 , the same way like service guard works with package IP addresses .

with two different physical MIC cards in the same subnet , HPUX has routing issues , that why its not recommended .

[Sridhar Bhaskarla]

Hi Marty,

Yes. You cannot have two IP addresses in the subnet on two seperate lan cards. It will create problem with the default route as the system will get confused as to which lan card it needs to use to send packets to the default router.

-Sri

[Marty Metras]

So if this is the case why would you want 2 NIC cards. The other one just sits there until the other one fails. Is there somthing I can change internal so I can use both NICs on the the same subnet. I'm not sure why you can do this. Please let me know more.
Marty

[Sridhar Bhaskarla]

Well, if you are willing to purchase a product called "APA" Auto Port Aggregation, then you can make use of both. But your NICs as well as the switches they are connected to should be supported by APA. Following document may help you.

http://docs.hp.com/hpux/onlinedocs/J4240-90016/J4240-90016.html

Multiple NICs can be used for backups, standby and heartbeats in ServiceGuard configuration, dedicated network etc.,

-Sri

[Patrick Wallek]

We have multiple NICs in almost all of our machines. 1 NIC is on the production network. The other is on a private admin network that ONLY exists within the computer room.

You can have active / standby NICs (ie. MC Service Guard).

There is also a product called Auto Port Aggregation that will allow you to have 2 NICs essentially act as 1 BIG NIC.

Have a look at more information on APA here:
http://software.hp.com/portal/swdepot/displayProductInfo.do?productNumber=J4240AA

[Marty Metras]

Well I guess I learned something again.
I would have thought you could have used 2 NIC cards to spread the load off.
I card has been just sitting there wait ing for me to do some thing with it.
Is this an HPUX thing or is this UNIX/Linux thing?
Oh Well....
Marty

[Marty Metras]

Here is another idea
http://www.hp.com/products1/unixserverconnectivity/infolib/cisco.html
Marty

[rick jones]

It is possible to configure two separate, physical NICs into the same IP subnet. It is however, not strongly encouraged.

What happens is that traffic will be accepted on both interfaces, but outbound traffic will only flow out one interface.

Now, if you set ip_strong_es_model, route lookups will include the source IP address, and this can have the side effect of forcing replies to go out the interface on which they arrived. If there is no source IP address at the time of the lookup (say an application calling connect() without first calling bind()) then I _think_ the behaviour is as if ip_strong_es_model is not set.

The other side effect of ip_strong_es_model is traffic will only be accepted on the interface with the corresponding IP address.

The strongly encouraged way to do load balancing across NICs is the aforementioned Auto Port Aggregation.

Now, I would have expected the NIC state going to disabled in SAM to be something else. When the NIC state is showing disabled in SAM, what does lanadmin show? If there are other HP-UX systems on the same stratch of network, can they be reached with the linkloop(1m) command?