Express Route Gateway migration not working and throwing error "Gateway subnet needs two or more address prefixes for migration"

Question

Express Route Gateway migration not working and throwing error "Gateway subnet needs two or more address prefixes for migration"

Answer 1

Hello sunil cherukuri,

Thanks for your question.

You will need to verify the current address prefixes allocated to the gateway subnet as The gateway subnet needs two or more address prefixes for migration.

To verify you can use the Azure CLI:

https://learn.microsoft.com/en-us/cli/azure/network/vnet/subnet?view=azure-cli-latest#az-network-vnet-subnet-show-examples

az network vnet subnet show -g MyResourceGroup -n MySubnet --vnet-name MyVNet -n <GatewaySubnet>

To add this See:

https://learn.microsoft.com/en-us/azure/expressroute/expressroute-howto-gateway-migration-portal#add-a-second-prefix-to-the-gateway-subnet

Please let me know if you have further questions

You can mark it 'Accept Answer' if this helped.