[u801e]

It does require that one open a port in their firewall for it to actually work. xdcc bots usually would indicate which port one needed to open.

[coatmatter]

Having open ports directly to the internet (by default) with dial up modems (before routers and NAT) used to be such a common practice. Things have changed, haven't they?

[freeflight]

That's a pretty good point I totally forgot about. Tho couldn't that problem "simply" be solved by updating the protocol to account for these changes?