IP address from forum posts?

[v8gaz]

It will point to the IP address your ISP has given your connection at the time. They don't change that often - maybe once every few months depending on the ISP, or when you reboot your router.

Unless you're a proper techie with a dedicated range of IPs...

[WTFH]

Unless you're a proper techie with a dedicated range of IPs...

"Range of IPs" = epic fail.

[Contreras]

How do you spoof an IP? It's a two way transaction so say your real IP is 200.12.12.12 and you connect with 150.11.11.11 but spoof as 100.13.13.13, surely 150.11.11.11 will send packets back to 100.13.13.13 and not to 200.12.12.12 since you are likely to be subnetted out?

I've never understood how that works!

It's impractical, for the reason you describe. It's of course easy to spoof a source address but then you wouldn't see the reply. The 3-way handshake needed to establish a TCP connection therfore becomes 'difficult'. As I understand it requires weaknesses in the network stack to succeed and any half-decent implementation will be hardened against this. Assuming you could get through "transmitting blind" so to speak, then that may be just enough to inject an attack, open a back door, etc. so theoretically possible but posting on CUK would be far fetched.

UDP though, without the 3-way handshake, would at least get past the network stack so it's up to the application make its own defence against spoofed IPs. One form of DDoS attack is to spoof the victims IP as the source address in a DNS lookup request (small UDP packet) sent to multiple DNS servers which then unwittingly each send DNS replies (larger UDP packet) to the victim and anonymising the attacker in the process.

LondonManc's mention re American Netflix content in the UK isn't really 'spoofing', at least not at the protocol level. It's bouncing traffic via a proxy, either a 3rd party managed service, or something you set up on a private server, the later being entirely feasible to cover a sockie's tracks but if going to those lengths you really would need to get out more.