APA Problem when assigning IP address

[PTX]

I have an RX6600 running HP-UX 11.31. I have aggregated a couple of the NIC's on the server. The aggregate (lan900) seems fine.

I have another interface (lan4) on the same subnet on the server... single NIC, not aggregated.

When I assign an IP address to lan900, I lose IP connectivity lan4. Can anybody explain this behaviour?

So... if I start a ping on lan4, then...

# ifconfig lan900 up
... lan4 stops responding...
# ifconfig lan900 down
... lan4 responds again...

Thanks.

[Tim Nelson]

A couple questions:

1)Are the IPs the same ? ( gotta ask )
2)Are the IPs on the same subnet ?
3) How are you assigning IP to lan900, ipconfig lan900... ?

[Torsten.]

>> I have another interface (lan4) on the same subnet on the server


This is IMHO the problem - the same subnet ...

[Tim Nelson]

I hate it when Torsten reads the parts of the sentences that I overlook :) That is why he has such a cool hat.

[Torsten.]

Tim, you will get these few points very soon, I'm sure ...

;-)

I count on you.

[PTX]

IP addresses are not the same.
Subnets are the same.

I simply...

# ifconfig lan900 x.x.x.x netmask y.y.y.y in order to assign the IP address.

As far as the same subnet goes, I can't imagine it's really a problem to have two IP addresses on the same server on the same subnet. I have an rp3440 here with two IP addresses on the same subnet running fine, with access to both ip addresses... it's been like that for 3 years now.

[Torsten.]

There are many related threads like this one:

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1087227

[PTX]

That thread doesn't really answer my question, though it does explain something I will need, that being the ip_strong_es_model, which I would have been looking for shortly. Thank you for that.

My problem still remains that I cannot ping any IP address on the server as soon as I enable the second IP address.

[Tim Nelson]

My experience is that HPUX has never done well with two IPs same subnet. The route does not know which interface to go over and probably is the cause of your issue.

I would recommend lan900 one subnet, lan4 another subnet. With APA enabled the need for redundancy is resolved. The need for two separate IP addresses on a system can be resolved by using virtual IPs.

i.e.

ifconfig lan900:1 xxx.xxx.xxx.xxx blah blah blah