[caiu] Fwd: Long BGP AS paths

[Rubens Kuhl]

Alguém notou esse efeito a partir de agora há pouco ?


Rubens

---------- Forwarded message ----------
From: William Herrin <bill em herrin.us>
Date: Sat, Sep 30, 2017 at 7:29 PM
Subject: Long BGP AS paths
To: "nanog em nanog.org" <nanog em nanog.org>


To the chucklehead who started announcing a 2200+ byte AS path yesterday
around 18:27 EDT, I beg of you: STOP. You've triggered a bug in Quagga
that's present in all versions released in the last decade. Your
announcement causes routers based on Quagga to send a malformed update to
their neighbors, collapsing the entire BGP session. Every 30 seconds or so.

For everyone else: please consider filtering BGP announcements with
stupidly long AS paths. There's no need nor excuse for them to be present
in the DFZ and you could have saved me a painful Saturday.

Cisco:

router bgp XXX
 bgp maxas-limit 50


Juniper:
https://kb.juniper.net/InfoCenter/index?page=content&id=KB29321


Quagga:

ip as-path access-list maxas-limit50 deny ^([{},0-9]+ ){50}
ip as-path access-list maxas-limit50 permit .*


Regards,
Bill Herrin


--
William Herrin ................ herrin em dirtside.com  bill em herrin.us
Dirtside Systems ......... Web: <http://www.dirtside.com/>