ros 5.22 connections tracking of firewall

tcp established timeout duration, have any effect on the user?
There is also a problem, for ppp dial-up users, if user A to obtain the address of the second he is 192.168.1.3, firewall connections through his connection tracking, but when he was off the assembly line, there is a dial-up user B, B user also may obtain the IP address to 192.168.1.3, then this user B, the B-subscriber will have any effect?

any users got same IP address at the same network would make conflict .. that would cause many problems
and if it work it would not work with stability