I have run into an interesting problem with a Juniper SRX 240 box. The box is running BGP as a border router, and is announcing a /24. To ensure that the vlan with the network stayed "up" I set the gigether-options loopback option on one of the interfaces which is part of an ethernet-switching bridge. This forced the vlan up, just as I wanted, and ensured the box did not withdraw the announcement in BGP when all servers behind the box were removed.
Sadly, the same option seems to wreck havoc on the ARP tables in the SRX. It causes 5-30 seconds long bursts of packet loss (around 5% over long periods of time) and I get duplicate answers to ARP queries.
- Is this behavior documented somewhere?
- Is there a better way to keep the vlan up?