> my company has a colocated server with 8 ip addresses.
> This sunday I cvsupped it to 4-stable. Before I rebooted I had 8 ip adresses
> with subnetmask 255.255.255.0.
> After the reboot it seemed that the ip adresses didn't work. When I tried:
> /sbin/ifconfig fxp0 alias 217.xxx.xxx.xxx it says:
> ioctl(SIOCAIFADDR): File exists
> This doesn't seem logic to me.
> When I try adding it with subnetmask 255.255.255.255 it works. This ip is
> accessible. However this doesn't
> seem logic to me because it shouldn't be able to reach it's gateway?
> Anyone who knows an answer to this?
> Ruben van Gogh
the netmask of an aliased IP must be set to 255.255.255.255 if it is on
the same network as the primary (actual) IP of that interface. This
stops broadcasts from that i/f being sent out for every IP and received
by every IP. I mis-configured this on a FreeBSD 2.2.6 box and the
console is unusable as it logs every unexpected packet! I hadn't
considered the other (routing) implication before but as this is a
special case and the machine 'knows' the netmask of the primary IP and
that this IP is an alias it has all the info. needed to get to a gateway.
Please correct me if I'm wrong.