2 networkcards in 1 system

[Olivier Nicole]

Hi,

>    and selected em1 and gave it its IP parameters
>     (I used the same hostname macos.cmi.ua.ac.be, in the DNS servers here
>      macos.cmi.ua.ac.be is assigned to two IP addresses)

First I doubt that this will work. You can assign several names to a
single IP address in DNS, but you cannot assign several IP to the same
name.

> (After rebooting,  em1 appears in the boot messages with the correct
> Mac- and IP address.. )
> 
> But I get many messages:
> Jan 13 11:05:25  macos kernel: arp: 143.129.XX.YY is on em0 but got reply
> from 00:1b:21:UU:VV:WW on em1
> Jan 13 11:54.25  macos kernel: arp: 143.129.XX.YY is on em0 but got reply
> from 03:ba:14:UU:VV:WW on em1

Let me guess, both NIC are connected to the same network? If so you
cannot predict what interface will reply first, so you can send a
packet through one interface and get a reply from the other interface.

In standard operation, you don't want to have your two NICs connected
to the same LAN with and IP in the same subnet.

> Or do I need to 'deconfigure' em1? How can I do that?

Edit /etc/rc.conf and remove all the lines that start with: ifconfig_em1

Olivier