Hello, and thanks for the prompt reply!

Opening an SSH session on my server's port (set to 6***, not the standard 23), I'm immediately feeling erratic behaviour: one time it takes 15 seconds to see the "ls -la" command appear in Putty, next time it'll show up instantly (it's not the server, load is low, memory usage within the limits).

So I'm firing up PP, go to the options to trace TCP packets on port 6*** (leaving all other values at default). All I see is: Destination address unreachable (100% packet loss) right after the router's address (192.168.0.254). Ethereal shows 192.168.0.254 sends back "Time to live exceeded" ICMP messages to 192.168.0.2, even when I take down the firewall. I must not be using the right settings.

When I stop the trace in PP, Ethereal reports packets out of order, retransmissions and many TCP Dup ACK while SSH commands are sent and acknowledged.