如何缩短TCP TimeWait时间？

As far as I know there is no way to forcibly close the socket outside of writing a better signal handler into your program, but there is a /proc file which controls how long the timeout takes. The file is

/proc/sys/net/ipv4/tcp_tw_recycle

and you can set the timeout to 1 second by doing this:

echo 1 > /proc/sys/net/ipv4/tcp_tw_recycle

However, this page contains a warning about possible reliability issues when setting this variable.

There is also a related file

/proc/sys/net/ipv4/tcp_tw_reuse

which controls whether TIME_WAIT sockets can be reused (presumably without any timeout).

Incidentally, the kernel documentation warns you not to change either of these values without 'advice/requests of technical experts'. Which I am not.

The program must have been written to attempt a binding to port 49200 and then increment by 1 if the port is already in use. Therefore, if you have control of the source code, you could change this behaviour to wait a few seconds and try again on the same port, instead of incrementing.