Subnet Mask issue

[redwings]

Hello Everyone,

I have just received a new 7028-6E4 server with AIX 5.1-005 on it. I have a question about the subnet mask. When I set it to 255.255.255.0 and I am on a network with that subnet, I can not access the network. When i change the mask to 255.255.240.0 it works. Is there an issue with using 255.255.255.0 on this server or on AIX 5.1? We have hooked up a laptop and used all the same setting and it worked fine. When trying to ping anything with the 255.255.255.0 subnet, it does nothing, even a trace can't find anything.

Any help is greatly appreciated,
redwings

 

[we2aresame]

Can you ask your Network admin to make sure you have the right idea about your company's subnet, I don't think there is any difference between AIX and Windows about subnet,thanks.

 

[redwings]

When trying to determine was was going on, I was working with our Network Admin. He is confused on why it does not work properly.

 

[we2aresame]

How many network adapters with your RS/6000? Can you post their detail configuration,like netmask, gateway?

 

[Chapter11]

the netmask is only going to come into play if you're trying to access a device that the netmask indicates is NOT on your current network.

we're going to need more details =D

 

[redwings]

We have two network adapters in this new server:

en0
Netmask 255.255.255.0
Gateway 10.253.4.1
IP 10.253.4.50

en1
Netmask 255.255.255.0
Gateway 10.253.4.1
IP 10.253.4.50

 

[Chapter11]

If both of these are plugged in, I wouldn't expect reliable behavior.

If you want to team up interfaces like that, you need to use an EtherChannel, which will also have to be supported on the network switch.

If they aren't part of an EtherChannel, turn one off or give it a different IP.

 

[we2aresame]

Is there any special reason you have to keep the 2 adapters with the same ip address? A unix box with 2 same ip addresses or even in same subnet would make the Tcpip didn't how to pass the adapters. Different mask make the Tcpip look the ip addresses as 2 different ip addresses in 2 different subnets, of course it works.

 

[redwings]

Is there a way to tell if I am running IPV4 or IPV6? If I am running IPV6 is there a way to change it to IPV4? Could this cause an issue if our network is running IPV4 and the server is running IPV6?

 

[MoshiachNow]

Also,

Have a look at this great link that helps calculating the netmask:

http://www.telusplanet.net/public/sparkman/netcalc.htm

"Long live king Moshiach !"

http://www.7for70.com/

 

[Chapter11]

The addresses you gave above are IPv4 - dotted quads. IPv6 addresses look different (off the top of my head I think they are given in colon-separated hex).

 

[redwings]

Ended up doing a rmdev on en0 instead of en1 and the issue with the subnet mask went away.

Thanks for all the help.