Hi Philip, thanks for the quick reply. We have indeed. Each of the Azure subnets we're making available over SD-WAN has an entry on the vMX and for traffic to/from any of our SD-WAN office locations, to/from any of the Azure subscriptions, we have end to end connectivity passing through the vMX and onto the relevant peered subscriptions. Where we seem to be getting stuck is passing traffic between 2 subs that are peered with the vMX Sub B. Each sub has a local route table attached to the relevant server subnet and these point to the LAN IP of the vMX as the next hop. The peering connection between the subs seems to make sure that connectivity is working. If I send traffic from Sub A to Sub C, the next hop leaving Sub A will be the vMX LAN IP and the vMX sees that traffic arrive in a packet capture but it never sees a response. The destination machine in Sub C (A linux box for simplicity, and tcpdump) never sees the packets arrive if they are coming from another Azure peered sub but has no issues if the source of traffic is from an SD-WAN connected location. But, you may have just sent me in a different direction... The Meraki Azure vMX setup guide has you creating a route table to attach to the vMX subnet but it doesn't mention having to do that anywhere else. I've assumed, up to this point, that I would have to add a route table individually to each peered subscription subnet but I now wonder if in fact all I need is to activate the gateway transit option and don't try to force traffic across the connection with an attached route table. OK, that's at least something I can test, I think, without breaking too many things. But I need another coffee first. Will report back as soon as I've updated things.
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