BGP error with “by remote host, open active delayed 27076ms (35000ms max, 28% jitter)”

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Have you seen below error? When you are onfiguring BGP.

"Oct 5 10:10:20.012: BGP: 129.186.17.1 open failed: Connection refused by remote host, open active delayed 27076ms (35000ms max, 28% jitter)"

I was wasting over an hour to figure out why BGP session was not established and kept getting weird error message.

Here is the why,

• The neighbor statement is incorrect.
• No routes to the neighbor address exist , or the default route (0.0.0.0/0) is being used to reach the peer.
• The update-source command is missing under BGP.
• A typing error resulted in the wrong IP address in the neighbor statement or the wrong autonomous system number. You need to check your configurations.
• Unicast is broken due to one of the following reasons:

– Wrong virtual circuit (VC) mapping in an Asynchronous Transfer Mode (ATM) or Frame Relay environment in a highly redundant network.
– Access list is blocking the unicast or TCP packet.
– Network Address Translation (NAT) is running on the router and is translating the unicast packet.
– Layer 2 is down.

• The lack of the ebgp-multihop command is a common mistake that keep peers from coming up. This issue is discussed in the second example.

 

In my case, issue was NAT. If you use NAT in the path to reach BGP neighbor I will cause a issue.