How to temporarily disable an Expressroute bgp peer session

Question

How to temporarily disable an Expressroute bgp peer session

Juaquin Jessup 25

We will be testing new VPN links that will route into our vnet and we need to know how to temporarily disable the BGP session on our ExpressRoute private peering. When I check the ExpressRoute>Private peering page of our ExpressRoute, I see a check box labeled "Enable IPv4 Peering", will unchecking this box and saving the settings disable the BGP session with the peer? Will the session re-establish once I check and save this setting? If so, approximately how long after disabling peering will the routes coming through this peer drop from the vnet route table?

Thank you

GitaraniSharma-MSFT 50,096 Reputation points Microsoft Employee Moderator

2023-05-24T11:35:34.0066667+00:00

@Juaquin Jessup , Just checking in to see if you had a chance to see the below answer. To help the community find the right answers, please do mark the post which was helpful by clicking on Accept Answer.

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Juaquin Jessup 25 Reputation points

2023-05-24T14:19:42.9033333+00:00

Thank you Gitarani.

Accepted answer

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GitaraniSharma-MSFT 50,096 Reputation points Microsoft Employee Moderator

2023-05-24T11:35:34.0066667+00:00

@Juaquin Jessup , Just checking in to see if you had a chance to see the below answer. To help the community find the right answers, please do mark the post which was helpful by clicking on Accept Answer.

And, if you have any further questions do let us know.
Juaquin Jessup 25 Reputation points

2023-05-24T14:19:42.9033333+00:00

Thank you Gitarani.

Answer 1

Hello @Juaquin Jessup ,

Welcome to Microsoft Q&A Platform. Thank you for reaching out & hope you are doing well.

I understand that you would like to know how to temporarily disable an ExpressRoute BGP peer session.

Yes, you can use the Enable IPv4 Peering checkbox under a particular peering to enable/disable the BGP peering in ExpressRoute.

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This is documented in the below article:

https://learn.microsoft.com/en-us/azure/expressroute/expressroute-howto-reset-peering-portal

When you disable a peering, the Border Gateway Protocol (BGP) session for both the primary and the secondary connection of your ExpressRoute circuit is shut down. When you enable a peering, the BGP session on both the primary and the secondary connection of your ExpressRoute circuit is restored.

To disable the BGP peering, you need to uncheck the box and then click the Save button. Only when you click save, the change will be applied.

Answering your other questions below:

Will the session re-establish once I check and save this setting?

Yes, the BGP session will re-establish once you check the Enable IPv4 Peering checkbox and click save.

If so, approximately how long after disabling peering will the routes coming through this peer drop from the Vnet route table?

On the MSEE devices, BGP keep-alive and hold-time are typically configured as 60 and 180 seconds respectively.

So, it may take about 5 minutes to drop the routes from the Vnet route table after disabling the peering.

Refer: https://learn.microsoft.com/en-us/azure/expressroute/expressroute-faqs#what-is-the-expressroute-bgp-hold-time-can-it-be-adjusted

Kindly let us know if the above helps or you need further assistance on this issue.

Please "Accept the answer" if the information helped you. This will help us and others in the community as well.

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