Can you actually fully connect to those ports from the outside? I recently moved to somewhere that is using Virgin Media broadband in the UK, and I noticed that

Can you actually fully connect to those ports from the outside? I recently moved to somewhere that is using Virgin Media broadband in the UK, and I noticed that when running "masscan" against my home IP from outside, it started finding ports that weren't actually open. On closer inspection it seems that either the router or the ISP has some sort of threshold over which it starts responding to all SYN's with SYN-ACK's, completing the second step of the three way TCP handshake. I assume it's some sort of port scanning interference system.