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Under extreme conditions, you might want the session to stay down until you manually<br />

restart it:<br />

[edit protocols bgp group session-to-AS65505 neighbor 10.0.31.1]<br />

aviva@RouterF# set family inet unicast prefix-limit idle-timeout forever<br />

Use the clear bgp neighbor command to restart the session:<br />

aviva@RouterF> clear bgp neighbor 10.0.31.1<br />

Cleared 1 connections<br />

After the session is reestablished, the Error line in the show bgp neighbor output<br />

reports Cease to indicate that the session was cleared:<br />

aviva@RouterF> show bgp neighbor 10.0.31.1<br />

Peer: 10.0.31.1 AS 65505 Local: 10.0.31.2 AS 0<br />

Description: EBGP to Customer A<br />

Type: External State: Active Flags: <br />

Last State: Idle<br />

Last Event: Start<br />

Last Error: Cease<br />

Export: [ send-statics ]<br />

Options: <br />

Address families configured: inet-unicast<br />

Holdtime: 90 Preference: 170<br />

Number of flaps: 3<br />

Error: 'Cease' Sent: 1 Recv: 0<br />

...<br />

See Also<br />

Recipe 13.15<br />

13.10 Authenticating BGP Peers<br />

Problem<br />

You want to ensure that all BGP protocol traffic that your router accepts from external<br />

ASs comes from devices known to you.<br />

Solution<br />

Configure MD5 authentication for your EBGP sessions:<br />

[edit protocols bgp group session-to-AS65505]<br />

aviva@RouterF# set authentication-key 1991$pOppi<br />

<strong>Discussion</strong><br />

Many external attacks launched against routing protocols are directed at BGP.<br />

Authenticating BGP packet exchanges on EBGP sessions prevents the router from<br />

accepting any authorized packets. The JUNOS BGP software supports MD5 cryptographic<br />

authentication.<br />

450 | Chapter 13: BGP<br />

This is the Title of the Book, eMatter Edition<br />

Copyright © 2008 O’Reilly & Associates, Inc. All rights reserved.

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