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Comment by iso1210 | Hacker News Reader

Looks like Centurylink/Level3 (as3356) might not be withdrawing routes after people close their peering?

That's what various networks have reported.

It kind of makes it hard to route around an upstream, if they keep announcing your routes even when there isn't a path to you!

Quick hack; split all your announcements in two, making the new announcement route around their old stale announcement by being more specific.

What could cause this? I wonder what the technical problem is.

We had this once with one of our former ISPs configuring static routes towards us and announcing them to a couple of IXPs. I have no idea why they did it, but it caused a major downtime once for us and basically signed the termination.

I would love to hear the inside scoop from folks working at CenturyLink. I’ve used their DSL for years and the network is a mess. I don’t know if it them here or legacy Level3 but i have a guess.

Edit: Looks like i would have guessed wrong :P. Still want that inside scoop!

Used level3 IP for a long time professionally with limited issues, ceratainly not on the list of worst ISPs.

Also used a company that over the years has gone from Genesis, GlobalCrossing, Vyvx, Level3 and now of course Level 3 is CenturyLink, which has been fine.

These are usually called 'BGP Zombies', and here's a good summary of their prevalence and usual causes: https://labs.ripe.net/Members/romain_fontugne/bgp-zombies

In this case however, it seems to be an L3/CL-specific bug.

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