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New Member

May I have your attention Please? Inquiry about BGP session initiation..

My question are:

When two routers initiate BGP session, is there any rule who will actively try first to estabilish the BGP session and the other end wait to receive the initation?

If there isn't such a rule, can it be adjusted for one end to try first?

Thank you,

Jinhong

  • WAN Routing and Switching
4 REPLIES
New Member

Re: May I have your attention Please? Inquiry about BGP session

i dont know any means of blocking that in BGP, but you can block it using access-lists on your interface. BGP uses TCP port 179 which if you block it one way using a firewall to allow only one of them to initiate the connection always.

New Member

Re: May I have your attention Please? Inquiry about BGP session

Thank you naveen,

Fistly, I didn't mean if any security feature can do that. But I just wanted to know its nature of initiation who will try first and if is there any option to satisfying this, command, to control one end initiate the session first and the other waits and reply to the initiation of the end initiating the session.

Thank you again naveen,

Any reply will be welcomed.

Cisco Employee

Re: May I have your attention Please? Inquiry about BGP session

You can use the following command to control which peer establishes the BGP session:

RouterA(config-router)#neighbor 2.2.2.2 transport connection-mode ?

active Actively establish the TCP session

passive Passively establish the TCP session

Both peers are in active mode by default.

Hope this helps,

New Member

Re: May I have your attention Please? Inquiry about BGP session

Thank you Hritter,

On Cisco 2600, IOS 12.3, I tried as your instruction and follows are the result.

As you can see there aren't such commands.

Your following comment will be highly appreciated

Regards,

Jinhong

Router(config-router)#neighbor 1.1.1.1 transport connection-mode passive

^

% Invalid input detected at '^' marker.

Router(config-router)#neighbor 1.1.1.1 transport connection-mode active

^

% Invalid input detected at '^' marker.

Router(config-router)#

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