In the same way the Hostiles works, but with port block. ie: blocking port 27016
In the original host list that was packaged with GTK, I found 226 listed with this port. In the fresh list after connecting, I found 232.
I realise this is only a small percentage compared to the entire size of the hosts files, but still a non-negligible amount of hostile hosts. All attempts should be made to prevent such hosts having anything whatsoever to do with GTK or any other client. This includes not helping them to connect if running as a UP or passing connection data to them if they are trying to connect. Just IMHO.
I have lots of experience with making requests for different apps and some devs saying great idea but then it gets low priority and basically forgotten about. :D
Quote from beginning of the GTK Hostiles file:
Hostile IP addresses, completely banned from the Gnutella network.
We don't accept connections from those hosts, never connect to them,
and drop their query hits on the floor without relaying them.
Extra note: I also noticed the DHT nodes list also had many hosts (between 10-15%) that would not have been allowed if using the 'Full' BearShare hostiles. And I was only checking the GTK hosts. None of these hosts used port 27016 however.
(Oops I removed the hash symbols from the quote as it mucked up the formatting.)