AIX

I have a bunch of servers on AIX, we have at least 2 NIC cards in each of them.

We upgraded them from AIX 4.2 to AIX 5.2. Since then when we reboot a server its always coming up with 2 default gateways. Habitually this is not a problem but sometime its causing some connection problem. We remove the 2nd gateway manually and then everything is fine until next reboot. We never had this problem with AIX 4.2.

When I'm looking in "smitty tcpip" both nic card are pointing on the same gateway so I'm really confused about where this can come from. I tried to find out but I didnt have any luck. I'm planning to have a script to remove it at boot time but i would like to have a cleaner solution or at least to know why its happening.

Anyone having a clue where i can fix that ?

A duplicate default route might lead to every second data packet getting lost.
A route that becomes active with reboot is either defined in the ODM or activated with the route add command from an rc file (most likely rc.net) that is called from inittab.
Check ODM routes with

Code:

# odmget -q attribute=route CuAt

Remove a route from the ODM with the chdev command that is accessible from the SMIT panel

Code:

 # smitty rmroute

If there are no entries in the ODM check for stanzas like

Code:

route add ....

in /etc directory.

Returns nothing:

Code:

# odmget -q attribute=route CuAt
#

I checked :

Code:

# cd /etc
# for file in `find . -type f`
> do
>    grep "route" $file | grep -v "^#" 
> done

and found no "route add defautl" matching the 2nd default gateway

Thanks a lot for the reply.

A default route does not need to be set with the word "default".... Btw. how is the first default route set?

When I "smitty tcpip", "minimum configuration", en0 or en1. I can see the default gateway address in that screen and it's the same address for both NIC cards.

There is no "route add" with the address specified as the second default gateway

Hm... First thought: The default gw that is visible in the minimum configuration is in the ODM. So we may have a problem here as you said odmget did not return any routing information.

Second thought: it would be wrong to use "minimum configuration" for more than one interface. This panel is meant to be used just once i.e. on first time configuration when setting hostname etc. For any other interface and all additional configuration the panel "further configuration" shall be used.

In case you did use minimum configuration twice I'd recommend to log in to the server through the primary interface. Use ifconfig to set the other (secondary) interface down, detach it, then rmdev -dl the en device to delete all information about it. Run cfgmgr to recreate the en device and then use "smitty tcpip, further configuration" to configure the second interface again.

Hi,
we had similar issues - and root cause was our nimserver - each time we connected to it, it put a second default route onto our box ... which can be savely removed.

Are you running etherchannel or do your nics have separate IPs?

Kind regards
zxmaus