Yikes, my bad. In the CSV file it didn't seem so large. I setup a dashboard where you can browse the longest as paths for the selected time period. check out demo-rv.snas.io:3000/dashboard/db/top-as-paths?orgId=2 [3]. Change the time range to see those longer paths. They are no longer current in the last hour since cogent filtered them.
--Tim On 01.10.2017 14:29, Tim Evens wrote: > The outliers are >100. Based on several peering points, <= 60 should be > fine. See attached CSV file that shows the top 120 distinct AS Paths > seen for the past month. Looks like 55644 likes to prepend a lot which > is pushing the length above 50. > > --Tim > > On 01.10.2017 09:16, marcel.duregards--- via NANOG wrote: > What would be a recommended value for a maximum as-path filter ? 50 ? On the > DFZ I've only 11 prefixes longer than 30 as-path, so for safety I would also > assume 50 as a max is well enough. Any advice ? Regards, - Marcel On > 01.10.2017 00:29, William Herrin wrote: 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 [1] [1] > Quagga: ip as-path access-list maxas-limit50 deny ^([{},0-9]+ ){50} ip as-path access-list maxas-limit50 permit .* Regards, Bill Herrin . Links: ------ [1] https://kb.juniper.net/InfoCenter/index?page=content&id=KB29321 [2] Links: ------ [1] https://kb.juniper.net/InfoCenter/index?page=content&id=KB29321 [2] https://kb.juniper.net/InfoCenter/index?page=content&amp;id=KB29321 [3] demo-rv.snas.io:3000/dashboard/db/top-as-paths?orgId=2
