i’d also hazard a guess that the ports you saw on dynamic IP weren’t actually open (or more likely closed). VM block a load of ports known to cause security holes/used by trojans (netbios ones), but for some unknown reason instead of just silently dropping traffic, they send back a port closed which shows the port as responding (but closed).
There’s a document somewhere which details the exact port numbers that are affected by this.
https://www.virginmedia.com/help/vir...internet-ports