Retroactive Port Scanning

[gkr75]

Hello

I was wondering whether there was a way to scan for the PID of a process that was listening on a port previously but isn't listening any more. I used lsof -i but the port doesn't show up under this command anymore bc according to the Network Utility Port Scan, the port in question is no longer listening. Is there anyway to go back and find the PID of this port?

Thank you

[Philip]

I don't think there is a log for that, unless the firewall keeps some type of connectivity logs.