topic Re: IP Address for NIC cards in Operating System - HP-UX

IP Address for NIC cards

Sarvesh A Dhuri — Sun, 12 Dec 2004 08:59:44 GMT

How many IP address a system administrator can configure on a single NIC card , I have HP UX 11i operting system (Hardware:- N class server) with two IP addresses mentioned on a single NIC card.
Thanks in advance

Re: IP Address for NIC cards

Steven E. Protter — Sun, 12 Dec 2004 10:11:47 GMT

How many do you want to configure?

On a practical basis if you are using a class C subnet, the most ip addresses you can configure is limtited by the network configuration.

Class C limit is 253 IP addresses.

I've never tried more than a couple of dozen. This was to provide ssl websites that needed their own ip address.

SEP

Re: IP Address for NIC cards

rick jones — Mon, 13 Dec 2004 12:16:55 GMT

There is no hardcoded limit to the number of IP addresses one can assign to a NIC under HP-UX 11i. There may or may not be practical limits - like the aforementioned number of IPs in a given subnet and the like - presented by your specific situation.

Re: IP Address for NIC cards

Stuart Abramson — Mon, 13 Dec 2004 12:59:18 GMT

Am I misunderstanding? I always thought that you could only configure -1- IP address per NIC card...:

INTERFACE_NAME[0]=lan1
IP_ADDRESS[0]=10.96.34.12
SUBNET_MASK[0]=255.255.255.0
BROADCAST_ADDRESS[0]=10.96.34.255
INTERFACE_STATE[0]=up
DHCP_ENABLE[0]=0

Are we saying that I can just keep on configuring IP addresses to the same card?:

INTERFACE_NAME[1]=lan1
IP_ADDRESS[1]=10.96.34.13
...
INTERFACE_NAME[2]=lan1
IP_ADDRESS[2]=10.96.34.14
...

MC/ServiceGuard let's you assign other IP addresses to the same card, so to speak, but you have to buy MC/SG.

Re: IP Address for NIC cards

Gary L. Paveza, Jr. — Mon, 13 Dec 2004 13:09:40 GMT

Stuart,

Yes, you can configure multiple IP addresses for a given NIC. In fact, ServiceGuard relies on this functionality.

For example, I have 2 hosts. Each host has a NIC with a static IP address on it. In addition, each host belongs to a ServiceGuard cluster. In that cluster are two packages - each with it's own static IP address (different than the first two). ServiceGuard actives those IP addresses on the NICs on the physical hosts.

It shows as

lan1 (host address)
lan1:1 (package address)

Note that you do not need S/G to do this.

Re: IP Address for NIC cards

Geoff Wild — Mon, 13 Dec 2004 13:18:13 GMT

Shouldn't be a limit on Unix - only the network as others have said.

And yes - multiple ips show as:

lan0
lan0:1
lan0:2

etc...in a netstat -in

Rgds...Geoff

Re: IP Address for NIC cards

Mark Greene_1 — Mon, 13 Dec 2004 16:14:08 GMT

See the man page for lanscan. If you lanscan -v, you'll see a column labeled NM ID. This is where the number to the right of the colon comes from in the "lan0:1" comes from. See the section in the man page for ifconfig under "IP Index Number".

mark

Re: IP Address for NIC cards

Sean OB_1 — Mon, 13 Dec 2004 17:01:13 GMT

Sarvesh,

There is no hard limit on the number of IP's you can configure. I believe the only limit is that they have to be on the same subnet.

You can have a primary and many aliases on a single NIC.

Re: IP Address for NIC cards

rick jones — Mon, 13 Dec 2004 17:29:47 GMT

The IPs do not even have to be in the same subnet these days - that was strictly an ancient HP-UX 10.20 limitation.

The point about NM IDs being a possible limiter is a good one to consider. I suppose a search of the include files might be in order, or of the MIB definitions - I believe it comes from the MIB definitions for ifIndex. If it is a short, then we are talking about 32 or 64K IPs. If it is an int then 2G or 4G.