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DDoS scrubbing center bounced our clean traffic back

Networking by kenji3 25 replies 4.5K views
sarahjey

Member

#21

CS student here with probably a dumb question: why does the loop stop after 90 seconds? Is there some BGP safety mechanism or did Contabo manually fix it?

Also, what is BCP? I saw kenji3 mention "their BCP kicked in."

learning on $5 VPS and prayers
nerdbann

Member

DNS Propagator

#22

sarahjey said:
Why does the loop stop after 90 seconds?

Probably their BGP flap damping or a prefix limit. When a route changes too many times in a short period, routers stop accepting updates for it. That's the "damping" part.

BCP = Business Continuity Plan, or in this context probably just their runbook for "stop the bleeding." Could be automated, could be a NOC human pulling a lever. 90 seconds suggests automated.

kenji3 said:
Their BCP kicked in

Kenji3, did you actually see traffic resume after 90 seconds or did the prefix just get withdrawn entirely?

kenji3

Member OP

#23

nerdbann said:
Did you actually see traffic resume after 90 seconds or did the prefix just get withdrawn entirely?

Traffic resumed, same path, same GRE tunnel. Clean route came back without the community. So they have some automated fix that reverts to last known good, or the damping expired and the correct route re-advertised.

I have the full pcap if anyone really wants it but it's 400MB of looped SYNs. Not very exciting.

Update: Contabo just replied to my ticket. They confirm "a routing policy template was incorrectly applied to clean-path advertisements from the Singapore scrubbing center." Fixed now, no recurrence expected. No mention of credits.

conbini > datacenter snacks
AL

Member

5 #24

I got the same copy-paste reply 20 minutes ago. "Fixed now, no recurrence expected." They didn't even change the template between customers.

Still no credit. I asked explicitly.

MeritBudi

Member

#25

ALPHA16 said:
They didn't even change the template between customers.

AI reply lor, confirm plus chop. Next time ask "are you a human" see what they say.

Kenji3, you should post this to LowEndBox forum also. More people need to know Contabo Singapore scrubbing got this problem. I help you write summary if you want.

XX

Member

1 #26

Has anyone tested since their "fix"? I just activated scrubbing on my Singapore VPS 30 minutes ago and the tunnel came up fine, no loop. But that's one data point, might be luck.

Also re: OVHcloud comparison, their Singapore scrubbing is €15 more per month for similar bandwidth. Not nothing if you're price-sensitive.

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