[ntp:questions] Client doesn't drop failed source

David Woolley david at ex.djwhome.demon.invalid
Sun Jan 31 09:39:25 UTC 2010

Danny Mayer wrote:

> How many connections do you think it takes to overwelm a server? Even on
> an idle connection TCP normally requires at least a minute of timeout

If you enable keep alives, the default timeout is several hours.  If you 
don't enable keepalives, there is no idle traffic at all.  You only need 
keep alives if there is no natural traffic in one direction.  Otherwise 
the first packet towards the side that has forgotten the connection will 
cause it to reset it.

> (lots of caveats, etc. here) but the server needs to drop these
> connections as quickly as possible in order to get the next one. Don't
> go there, there's a lot more going on under the hood than you seem to
> realise from this response.

TCP is actually designed to produce minimal idle traffic.

As noted elswhere, there are other reasons for not using TCP for NTP.

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