Op 7/14/2010 9:19 PM, Peter Stuge schreef:
Agree, you have to take a conscious decision, keepalive is not all moonshine and roses.Beware. Enabling TCP keepalive is not neccessarily a feature. For example on a laptop which may have intermittent VPN connectivity, Iconsider the keepalive default in Linux to be really superior.
But, on servers on a fixed network with time critical connections where connections should fail over to another node or bomb out with fireworks as soon as a connection is broken, not having keepalive is killing. The same applies to an application that uses
dozens of connections, you might run in to a situation where you are tending a socket graveyard.Point is that the default on Linux ( sockets have no keep alive enabled ) can not be changed.
It can be changed on *BSD and a lot of BSD derived TCP/IP stacks. The application MUST call setsockopt to turn it on.And it's still fine if you can afford to check and maybe change some application you use (that is the cost and advantage of open source), but a pain if you happen to be forced to use an application that doesn't set keepalive. I ran into it with rexec, which could not easily be changed due to all kinds of non-technical issues. I was a bit shocked to find out that Linux doesn't support setting the system default so that every socket created would
have KEEPALIVE enabled. I can't see the advantage of not supporting that. The SSH keepalive options might mitigate this, but I did not try,
so no idea.
Yeah, they'll do the trick too.
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