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SubjectRe: > 15K simultaneous connections EXAMPLE program/OS config needed, was: Re: POSIX aio vs completion ports
Rogier Wolff wrote:

> [...]

> If you're handling lots of outgoing connections (unlikely), you might
> run into trouble. Suppose we want ephemeral (sp?) ports, the kernel
> might say "Sorry, none found" when you've used all of them. This is
> incorrect (but nobody has run into it yet). After one round around the
> port space searching for an unused port, the kernel should just
> allocate a port that's already used. Then you can connect to any
> IP/port, except the one that the existing connection is already
> connected to. If the kernel knows the destination IP/port at that
> time, it should try to avoid that situation. Otherwise, it should just
> hope for the best.

I'm not sure what you are saying here. I've never hit the limit, even during
flood testing stuff, so I don't know what actually happens. Are you implying
that other Unixen reallocate an already used port, without the use of
SO_REUSEADDR, or that you think they should? I had always assumed, but never
explicitly read, that without SO_REUSEADDR there would never be reuse of the
local port.

One PITA with port allocation is that you can't reserve the darned things.
You are running a server. It dies. You try to restart it, and find some
client type program has just been allocated your port. Ugh!

Steve



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