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Azure Networking Blog

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Customisation controls for connectivity between Virtual Networks over ExpressRoute

Microsoft

May 22, 2024

Contents Overview Context What changes are happening? ExpressRoute Virtual Network Gateway Azure Virtual WAN (VWAN) VWAN Hub-to-Hub - Same Virtual WAN parent resource VWAN Hub-to-Hu...

Updated May 22, 2024

Version 1.0

azure expressroute

virtual wan

adstuart

Microsoft

Joined July 16, 2019

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EdonB

Copper Contributor

Jul 25, 2025

Very well explained, Adam!

I have a question:
Is it allowed to advertise the default route (0.0.0.0/0) via BGP from one hub to another, but not to on-premises, when both hubs are connected through the same ExpressRoute circuit, using two separate ER gateways?

The reason I’m asking is that we’re currently migrating from a customer-managed hub to a VWAN hub, and I need to enable internet connectivity through an NVA located in the customer-managed hub, which should be reachable from the VWAN hub.

Connectivity from the VWAN hub to the customer-managed hub (where the NVA resides) is working — BGP routing tables are being updated correctly. However, I haven’t advertised the default route yet, as I’m unsure whether this setup will allow internet traffic from the VWAN hub to flow through the customer-managed hub.