all network people please review this proposal: because someone is going to commit it soon. D5017

[Julian Elischer]

Unless eri gets to it first I will.

see https://reviews.freebsd.org/D5017

If you have a server, you can put an arbitrary number of clients on 
the same port number because they all have different addresses.

However in the case of a client accessing multiple servers we are 
limited to 65535 sessions because we strictly don't allow the same 
port to be used more than once. This is silly because TCP is a 
symmetrical protocol and of it works for the server it should work for 
the client.

So this patch changes the allocation of ports to allow the client to 
use a port that has been used before as long as the previous port user 
is not talking to the same host/port. This removes the limitation of a 
freebsd machine being only capable of contacting 65000 hosts in a 
single port shutdown timeout period. With modern machines capable of 
initiating  MILLIONS of sessions per second, having a limitation of 
65000 per 2 minutes is a bit silly.


Please read the patch if you suspect this will have a bad effect of 
any sort.  Once the session is started there is no record as to who 
started it so any issues would have to be in the startup phase.


Julian