Should I enable "tcp_tw_reuse" on my server?
tcp_tw_reuse allows reusing a client port immediately after the connection has been closed, even though the connection is still in TIME_WAIT state.
This setting should not be applied when communication with hosts behind a NAT firewall needs to take place. Otherwise, you might encounter strange TCP connection issues after applying this configuration parameter.
The most known issue has clients behind NAT receiving the following error when connecting via FTP:
425 Unable to build data connection: Connection refused