The following is given in the book TCP IP Illustrated by Stevens
Quiet Time Concept The 2MSL wait provides protection against delayed segments from an earlier incarnation of a connection from being interpreted as part of a new connection that uses the same local and foreign IP addresses and port numbers. But this works only if a host with connections in the 2MSL wait does not crash.
What if a host with ports in the 2MSL wait crashes, reboots within MSL seconds, and immediately establishes new connections using the same local and foreign IP addresses and port numbers corresponding to the local ports that were in the 2MSL wait before the crash? In this scenario, delayed segments from the connections that existed before the crash can be misinterpreted as belonging to the new connections created after the reboot. This can happen regardless of how the initial sequence number is chosen after the reboot.
To protect against this scenario, RFC 793 states that TCP should not create any connections for MSL seconds after rebooting. This is called the quiet time
Few implementations abide by this since most hosts take longer than MSL seconds to reboot after a crash.
Do operating systems wait for 2MSL seconds now after a reboot before initiating a TCP connection. The boot times are also less these days. Although the ports and sequence numbers are random but is this wait implemented in Linux?
Also RFC 793 says that this wait is not required if history is maintained. Does linux maintain any history of used sequence numbers for connections to handle this case?