Route advertisement from vWan to ExpressRoute / VPN over BGP

Question

Hello Experts,

Would you help me understand what prefixes will be advertised out from the VPN connection or Express Route ( over BGP ) if we have vWAN deployed over three regions - East, East2 and West.

Should we expect only regional prefixes to be advertised ? ( e.g. EAST2 VPN or ER will advertise only prefixes of VNETs connected to EAST2 region ) or all prefixes ( east2+west+east) will be advertised over bgp ?

Thank you !

Answer 1

Hello anonymous user-2512 ,

Azure VPN gateways support BGP transit routing with the exception that Azure VPN gateways will NOT advertise default routes to other BGP peers. To enable transit routing across multiple Azure VPN gateways, you must enable BGP on all intermediate VNet-to-VNet connections. For more information, see About BGP.

So it depends on your network architecture. If you have enabled BGP on all the intermediate connections then all prefixes will be advertised.

Kindly let us know if you need any further assistance on this issue from our end.

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