Can a website identify a specific laptop?

FarmerHorse

Interestingly I just tried again and this time DS has created a new account. I doubt if I'll use it; the place isn't what it was 20 years ago.

The only difference now is that we have a different ISP, which suggests that the router IP is at least part of the check. That suggests that if someone else in your household has been a naughty boy no-one else can sign up from your LAN (unless specific info from the PC is included...)

You probably know this, but your PC's IP address is most likely to be 192.168.n.n, or 10.0.n.n, just like millions of other domestic devices across the UK and around the world are. Internal LAN IPs for domestic users are most likely to be in the 192.168 / 10.0 ranges. It's the external public-facing IP that's unique. 

Jenni_D

There is a lot of header information that can be read when a browser connects to a website.

https://en.wikipedia.org/wiki/List_of_HTTP_header_fields

So it is quite easy to get IP address info and/or proxy address info (HTTP-X-FORWARDED-FOR), but obviously not local network address info.