Graceful Shutdown should only be done on eBGP sessions. If you alter the local-pref on ibgp sessions it is possible to produce loops or other network instabilities. Now if all iBGP routers apply the same rule it is fine but if not you can get into trouble.
So better adjust our example and only apply the rule to ebgp peers. Btw. RFC8326 mentions explicitly that GRACEFUL_SHUTDOWN should only be applied for eBGP sessions. -- :wq Claudio Index: etc/examples/bgpd.conf =================================================================== RCS file: /cvs/src/etc/examples/bgpd.conf,v retrieving revision 1.21 diff -u -p -r1.21 bgpd.conf --- etc/examples/bgpd.conf 2 Feb 2021 00:34:03 -0000 1.21 +++ etc/examples/bgpd.conf 19 Sep 2023 07:38:36 -0000 @@ -111,7 +111,7 @@ allow from any inet6 prefixlen 16 - 48 # Honor requests to gracefully shutdown BGP sessions # https://tools.ietf.org/html/rfc8326 -match from any community GRACEFUL_SHUTDOWN set { localpref 0 } +match from ebgp community GRACEFUL_SHUTDOWN set { localpref 0 } deny quick from any prefix-set bogons
