How to correctly use 2 on board nics

[Tom Judge]

John Nielsen wrote:
> Quoting Ivan Carey <ivan at careytech.com.au>:
>> I have a server board with 2 onboard nic's
>> I have set them up in rc.conf as follows
>>
>> defaultrouter="192.168.1.1"
>> network_interfaces="em0 em1 lo0"
>> ifconfig_em0="inet 192.168.1.3 netmask 255.255.255.0"
>> ifconfig_em1="inet 192.168.1.4 netmask 255.255.255.0"
>>
>> The question, is this the correct configuration?
> 
> Manually specifying network_interfaces is deprecated (take that line 
> out). Putting both NIC's on the same subnet and segment but with 
> different IP's like this may not be too useful..
> 
>> If I have both nic's connected to the switch I can ping 192.168.1.1 
>> and 192.168.1.3 and 192.168.1.4
>>
>> If I have only em0 connected I can ping 192.168.1.1 and 192.168.1.3
>>
>> If I have only em1 connected I can ping 192.168.1.3.
> 
> That is because the route to 192.168.1.1 is associated with em0 at this 
> point.
> 
>> What could the 2 onboard nic's be best used for. I was thinking that 
>> in the event on was to fail then the other would still be ok.
> 
> For that to be most useful you'll want to set something up so they can 
> share the same IP. The lagg(4) (link aggregation) virtual interface has 
> already been mentioned, but I believe it is still only available in 
> -CURRENT. Other possibilities might include attaching ifconfig scripts 
> to link up/down events or [lack of] ping responses on one or both 
> interfaces.
> 
> JN

I thought I saw if_lagg MFC'd to RELENG_6 a few weeks back on 
cvs-src at ...  After checking cvsweb it is available in RELENG_6.

Tom