Your ports, opened properly — or told the truth about
Getting a HighID means your router has to forward the ports eMule listens on. eMule Qt does that for you, using three different protocols and then checking whether it actually worked.
- PCP (RFC 6887) — preferred. Works on IPv4 and IPv6, reports the port and address it actually assigned, and signals when the router has rebooted.
- NAT-PMP (RFC 6886) — IPv4, common on OpenWrt and older Apple hardware.
- UPnP IGD — the fallback, IGD1 for IPv4 and IGD2 for IPv6 firewall pinholes.
All enabled backends probe your router at the same time behind a three-second deadline, rather than trying them one after another. The winner is remembered and tried first next time, and the losers’ mappings are released so your router is not left holding duplicates.
Graded on the port you actually got
ED2K advertises the port from your preferences and has no way to announce a different external port — so a mapping granted on some other port is a silent LowID. eMule Qt therefore grades candidates on whether your exact port was granted, and an exact match beats protocol preference: a UPnP router that honours your port wins over a PCP router that does not. Only on a tie does the PCP → NAT-PMP → UPnP order decide.
Status is reported honestly rather than flatteringly. Mapped means forwarded and reachable. Degraded means the router granted something that will not work from the Internet — usually a different external port, or an external address that is not publicly routable, with CGNAT the common case. Showing that as success would put the word “forwarded” next to a permanently firewalled client.
Only what needs opening is opened: the ED2K TCP port, the client UDP port, the web server port if you have enabled it, and matching IPv6 pinholes. The server UDP port is deliberately left alone — it only ever receives replies to requests you sent first, so your own outbound packet already opens the path, and an inbound mapping would be attack surface for nothing.
Why it matters
No router admin login, no static LAN address, no manual renewal — and when your ISP’s CGNAT makes forwarding impossible, the client says so instead of pretending.