lan0 stops working when lan1 is configured

[Jan de Haas_3]

Hi,

Got a problem which appears very strange. We've got a server with 2 lancards.

The first one is connected to the production lan, the second one is connected to the backuplan.

When I configured the second lancard (it was not yet used at all before this) with an IP address, we lost connectivity to the primary lancard!

Checked, doublechecked, both the existing IP and the new IP were on different subnets. Once I unplumbed the second (lan1) interface card, connectivity to the first lan (lan0)interface was possible again...

This seems to be very weird behaviour. Has anyone experienced this before or have an explanation?

Thanks,
Jan.

[RAC_1]

anything in syslog?? In netfmt log??
netfmt -f /var/adm/nettl.LOGXX

[Jan de Haas_3]

Already sorted, forgot to add the subnet mask to my ifconfig command. Both lancards were configured with IP addresses from the same range. So the second card defaulted to the default subnetmask for that IP (A-class).

10.1.2.32 (SN 255.255.255.0)
10.1.3.21 (SN 255.0.0.0)

Think it's time for coffee...

[Jan de Haas_3]

Resolved.