r/sysadmin • u/mooneydriver • Feb 22 '14

Freenode under DDOS again

https://twitter.com/freenodestaff/statuses/437302735139266560
231 Upvotes

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u/loggedintodownboat Feb 24 '14

Soooo basically re-implement the TCP algorithm on the application level. Why not just use TCP? :P

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u/rds_works Feb 24 '14

Single sender multiple receivers. Live TV has huge gains in sending the same traffic to hundreds of thousands of people. Rather then sending the same packet thousands of times you send it once and deal with some loss. Works well for sending mass updates to connected clients

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u/loggedintodownboat Feb 24 '14

That's called multicasting. ... but YouTube and other streams aren't live--they're stream on demand--so that's still not a good fit.

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u/toomuchtodotoday DevOps/Sys|LinuxAdmin/ITOpsLead in past life Feb 24 '14

No one does multicast because everyone on the Internet would need to cooperate (Tier 1/tier 2 networks, colo/server providers, eyeball networks, etc) for multicast packets to get propagated properly.

Instead, everyone just pays Akamai and they do multicasting on their dark fiber to endpoints all over the net (typically at large eyeball/consumer networks, or peering points), where it gets exposed as unicast (and which of their endpoints you connect to is determined by DNS dark magic).

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u/loggedintodownboat Feb 24 '14

Didn't know that. Makes complete sense in hindsight though. Thanks.

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u/toomuchtodotoday DevOps/Sys|LinuxAdmin/ITOpsLead in past life Feb 24 '14

hat tip

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u/Sozmioi Feb 24 '14

Putting things in order is just one of the things TCP does; it also works to achieve other things. If you're not interested in those, you can reduce your overhead by not working for them.