@jdsilva  That's one thing we don't have to worry about as we run fixed IP for everything. (something else we inherited!) I disabled DHCP on both interfaces on both MXs before we tried going live.   @T-800 I'll take a look at those articles thanks.   EDIT Following a call with Meraki Technical sales this morning it is clear we have a non standard/recommend network setup, Meraki do not support two live active MXs on the same network! We will have to make changes to our network setup to get them to work properly and hopefully improve the network in general. In light of this @T-800 I've marked your reply as the solution.   Many thanks to all that have contributed to this thread it has been very enlightening and now looks like I have quite a bit of learning and work to do.   Ian       ... View more

I had checked firewalls but missed the default gateway! We have two internet links and the PCs with the MX as their DG were the only ones i could ping. Everything else is still on our primary link on an old ASA 5510.   Thanks Ian   ... View more