Your reseller asks for your device's MAC address. You have no idea what that means. British IPTV resellers using stalker-based IPTV reseller panel systems (common for MAG boxes and some smart TV apps) authenticate by device MAC address instead of username/password. Specifically, a MAC address is a unique identifier for your device's network hardware. The IPTV panel links your subscription to that specific MAC. The advantage: you never type a username or password. The disadvantage: you cannot easily switch devices. I have helped users migrate between both systems. Each has valid use cases. What actually works is understanding which method your British IPTV reseller uses before you subscribe. M3U (username/password) is more flexible—use it on any device, any app, anywhere. MAC registration is simpler for non-technical users but locks you to one device. A good IPTV reseller will offer both from the same IPTV panel. Let me give you a real example. A user in Sheffield bought a MAG box specifically because it was simple. His IPTV reseller asked for the MAC address, entered it into the IPTV reseller panel, and the box worked immediately. No passwords. No URLs. His elderly parents could use it without help. When he traveled, he asked the reseller to temporarily switch his MAC to his laptop's network adapter. The reseller did it in two minutes. That flexibility worked for him. Another user bought the same service but wanted to switch between his phone, tablet, and TV. The reseller gave him an M3U URL instead. He uses the same login everywhere. The pattern that keeps showing up among flexible British IPTV operators is this: they store both a MAC and an M3U credential for every user. You can switch between them by asking. A credible IPTV reseller also has a self-service portal where you can change your registered MAC address yourself without emailing support. That is rare but excellent. One more thing. Some IPTV panels allow "multi-MAC" — one subscription linked to up to three different device MAC addresses. That is the best of both worlds: simplicity for each device, flexibility across devices. Before you subscribe to any British IPTV service, ask: "Do you support MAC address registration, M3U, or both?" If you plan to use multiple devices, M3U is usually better. If you have one dedicated streaming device and never switch, MAC is simpler. That said, never give your MAC address to a reseller who seems untrustworthy. With your MAC and their IPTV panel access, they could theoretically spoof your device. Unlikely, but possible. Use M3U for higher security.