VXLAN Gateway Flapping

[ombai]

So I’m running into a weird issue with VXLAN. We’ve got two sites (A,B). IPSEC tunnel between Loopback interfaces. VXLAN running over the tunnel. VLAN sub-interface on each end that is then a member of a software switch along with another vlan that we can assign to switch ports.

So far everything works. Site A VXLAN devices can communicate with Site B VXLAN devices as expected, as well as reach the web from their respective firewalls wan port.

Here’s the weird bit. If I ping a device (SMB, RDP, etc) inside the VXLAN (SiteA inside) from a device at Site B outside the VXLAN, the gateway for the Site A device temporarily shifts to send all traffic out the SiteB gateway before switching back to go out its own sites gateway a few seconds later.

Any insight would be awesome!

[RobeBris]

Hello !
Which FortiOS version did you have?