>> We're having to shut eth1 down and bring it up for sync at night. > > To what type of equipment are your ethernet devices connected? I'm asking now. > Are they > both connected to the same device? Same VLAN, not sure about same device yet. Checking. > I've seen some devices (particularly > 2Wire) that do not like two interfaces from the same system connected to > them. Reading the arp_filter settings it does match what we're experiencing, but I've never seen it before, but haven't ever been looking for it. Maybe because this is SIP/RTP traffic vs normal data traffic which when the switch switches the MAC <-> IP ARP mappings the voice traffic drops. You wouldn't noticed that on normal data traffic. arpwatch is picking up the flip flops. > You note that eth1 is on a 169.xx IP, and earlier in your email, you note > that it's non-routable. Perhaps that's not the wording you wished, to use, > or perhaps you meant that it's not routed out to the internet, however, > 169.xxx.xxx.xxx is most certainly a "routable" IP block, as far as > internet standards go. You're right. We're using 169.0.0.1-2 when we shouldn't be! It should be either in the ranges below or 169.254.x.x. Doh! > The only "non-routable" (i.e. reserved for private networks) IP blocks are: > > 10.0.0.0 - 10.255.255.255 > 172.16.0.0 - 172.31.255.255 > 192.168.0.0 - 192.168.255.255 > > While certainly not an undertaking to be done lightly, you may wish to > renumber your internal network. For two DRBD interfaces this will be fine but will need an umount or schedule reboot for the pair. Thanks, Gavin.