Really like to know what the next-hop IP points to for ASN 65515 in Azure express route !!!!

Question

What do IPs in red point to ?

thanks !!

Answer 1

Hello Gongya Yu ,

Thank you for reaching out on the Microsoft Q&A .

In Azure ExpressRoute, the concept of a specific next hop IP for ASN 65515 doesn't quite apply as it would in a traditional network setup. ASN 65515 is used internally by Microsoft's routing infrastructure, and ExpressRoute relies on Border Gateway Protocol (BGP) to dynamically choose the most efficient path for your traffic based on current network conditions. Therefore, the next hop IP address will vary and isn't a fixed entity you can directly connect to. The example IPs you mentioned, 192.168.0.13 and 192.168.0.12, are private IP addresses typically used for internal networking within an organization and aren't relevant to Azure's internal routing. Essentially, Microsoft's internal routing efficiently manages your data packets, so you don't need to be concerned with the specific next hop IP for ASN 65515.

I hope this helps! If you have any further questions, feel free to ask.

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Answer 2

@Gongya Yu

Thank you for reaching out.

I understand you wish to know which is the next-hop IP points to for ASN 65515 in Azure express route.

The ASNs from 65515 is reserved for internal use, the IP addresses in the route are the private IP address configured for private peering.

More details regarding the ASN can be found here

The dual eBGP peering that the MSEE establishes for each ExpressRoute peering is transparent at the control plane level. Therefore, when you view an ExpressRoute route table, you see the virtual network's ExpressRoute gateway ASN for the VNet's prefixes.

Reference:

https://learn.microsoft.com/en-us/azure/networking/connectivity-interoperability-control-plane?toc=%2Fazure%2Fexpressroute%2Ftoc.json

Please let me know if you have any additional questions. Thank you!

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Answer 3

thanks so much!!

I am always feeling MS makes something working without telling the users how.