alias interfaces

[George C. Kaplan]

On Jul 28, 2006, at 2:41 AM, Simon Hobson wrote:

> garry saddington wrote:
>
>> I am trying to set up load balancing using LVS-DR and need to  
>> start DHCP
>> on an alias interface - eth0:240. Is this possible or am I wasting my
>> time.
>> I am getting this:
>> No subnet declaration for eth0:240 (0.0.0.0).
>
> DHCPD cannot use anything but a real interface - because it needs to
> receive and send broadcast packets which (almost) by definition
> cannot belong to an alias interface.

Actually, dhcpd can use an alias (I'm doing it on FreeBSD) if you  
compile the server with USE_SOCKETS and use the 'local-address'  
option in dhcpd.conf.  I'd guess this would work on a loopback  
interface as well.

Note that with this setup dhcpd will not be able to receive  
broadcasts, so it can't provide DHCP service on its own subnet.  But  
it'll work for other subnets that have a DHCP relay agent.

-- 
George C. Kaplan                            gckaplan at ack.berkeley.edu
Communication & Network Services            510-643-0496
University of California at Berkeley