So I have setup two mikrotiks running VLANS, on top of VRRP, on top of bonded interfaces. I am doing this because I have more VLANs than interfaces that I want to get higher aggregated interface throughput. All is working OK but I am having weird MTU issues. I have gone through the various posts regarding MTU and L2MTU calculations but no values I set seem to work. I cant find any post in this configuration to determine if the VRRP config also alters the attached packet size or not.
So the setup looks like this
-> Eth1, Eth2, Eth3 Bonded
--> VRRP established and working on bond
----> VLAN configured on VRRP interface
------> IP address configured on VLAN interface
------> Second IP address configured on second VLAN interface
---------> Routing between the two VLAN interfaces
With all MTU set at the default 1500 I get a lot of broken packets and connection timeouts, as I lower this on the VLAN interface much of this is resolved but I still get a lot of connections failing to respond.
This started working briefly, when it did the L2 MTU values all changed by themselves to the correct ones, and everything was fine, disabled and re-enabled the bonded interface and everything set back to the default 1500 values and it all broke again. Could this be MTU path discovery not working? Or is there something else which sets the L2 MTU?
When working all the MTU values were 1500, and the bonded and vrrp L2MTU was automatically changed to 1510, and the VLAN L2MTUs changed to 1506. I cant work out how to get them back to those values.
Any help would be greatly appreciated!!