Network settings; where are they stored?
 

what config file (path and name) are the network settings stored? i know DNS is /etc/resolv.conf but where is the ip, gateway all that good stuff kept?

Sorry. I missed that this was AIX specific...

If you want to know things, "ifconfig -a" works rather well, as in a lot of Unix systems.
If you want to change settings, "smit tcpip" is a AIX menu-driven way to do that. Not the only one, but it works fine.

They are not stored in a flat file, but in the ODM. They are set with the chdev command, but as zorba says, using smit or websm is easier to start with (and probably to end with).

e.g. to show current settings of ethernet adapter 0
note : AIX distinguishes between the physical adapter (ent for ethernet) and the logical device (en for standard ethernet), in a way that is a little confusing at first but makes quite a lot of sense once you get used to it.

For instance if you gather up several physical ent adapters to create a single hyperchannel tube, which is administrated as a single logical enXX adapter.

ahh, not stored in a specific file.

I've been reading about the physical and logical ethernet adapters, from what i gather even if the physical goes down the logical can carry on talking to the other logical partitions or something.

@Frustin : OK, you start understanding. Physical adapter, logical driver, gathering several physical adapters in a logical driver giving a single IP address. But Logical Partitions is something else, dealing with CPU's.

ok perhaps i dont.

Frustin,

You might be thinking of the ability AIX has to have high availability IP addresses. The idea is that you can have a virtual IP address (VIPA) which sits behind two real adapters. If one adapter fails, it carries on using the other one.

This isn't really anything to do with the ent/en (hardware/interface) distinction at the adapter level though. There isn't a case where the failure of a physical adapter doesn't also cause the logical interface for that adapter to fail; merely that the IP address can be transferred to a different adapter.

is this etherchannel? does it cope with load balencing, that sort of thing?

Kinda... sorta.

What you are talking about here is the Virtual Ethernet, which is available on the new power5 platforms with AIX 5.3 only. The partitions within the machine can talk to each other through the hypervisor on a network that runs about 1 - 3 Gb/s.

Etherchannel can work in a load balancing mode, but that requires that both/all of your adapters be plugged into the same switch generally. I think this only works on Cisco switches. However, there is a backup mode that it can operate in, which will allow you to plug into two different switches. If the primary fails then it will automagically switch over to the second adapter. We use this alot around here, and it works beautifully.

I am running 5.1 and the VIPA was available to me. Albeit i didnt have the option to add ethnet channels.

i am still confused with the difference between VIPA and etherchannel.

Essentially there is very little difference in the way the function. VIPA will work across two switches and broadcast multiple addresses, one of which is a "highly available" address. Etherchannel broadcasts a single address.

The other bit of fun with with VIPA is having to set up gated.conf. This part of VIPA confused me, as I am by no means a network type person.