UPnP maps port correctly, but uses wrong protocol (UDP instead of TCP)

Search (both google and forums) produced no results, so I now post my question:

uTorrent 1.8 Beta (Build 8912) seemed at first to have difficulty mapping a port using UPnP . Upon further investigation, I learned that it *is* mapping a port and forwarding it to my computer, but it is choosing to use UDP rather than TCP.

When only the UDP protocol is used, the uTorrent Port Checker (http://www.utorrent.com/testport.php?port=MyRandomizedPort) fails and says the port is not open. However, simply by changing the protocol from UDP to TCP from within my router configuration page and re-running the test, the port is now open and I am in business.

Is uTorrent supposed to map my ports using UDP? I always thought it was supposed to use TCP. Any way I can tell uTorrent to use TCP instead of UDP as my default protocol for port mapping? My router is a Network Everywhere (Linksys) NR041.

Thanks.

That sounds like your router not liking multiple rules with the same display name.

Have you checked the UPnP packets with wireshark to see if both rules are being created?

DreadWingKnight, I think you're on to something. I have not checked with wireshark yet, but indeed, I can only select one protocol or the other while in my router settings page. In the port forwarding section, there sits an entry with the uTorrent display name and the UDP box checked. If I then check the TCP box, it *switches* the checkbox from UDP to TCP. In other words, it acts like a radio button--only allowing one protocol or the other.

Sounds to me like I may be stuck if the router doesn't like multiple rules with the same display name... or not?

If you port forward TCP, some routers (like Netgear) assume you also want to allow UDP on that port as well.

Router bug.

DreadWingKnight, I think you're on to something. I have not checked with wireshark yet, but indeed, I can only select one protocol or the other while in my router settings page. In the port forwarding section, there sits an entry with the uTorrent display name and the UDP box checked. If I then check the TCP box, it *switches* the checkbox from UDP to TCP. In other words, it acts like a radio button--only allowing one protocol or the other.

Sounds to me like I may be stuck if the router doesn't like multiple rules with the same display name... or not?

I sent a test build to the email address on your forum account.

Hello,

Confirming: I have same problem (router is Zyxel prestige 660 series). uTorrent creates "uTorrent (UDP)" mapping - yes, it even has "UDP" in mapping name. No problem to create couple of these mappings from different PCs so using same name for multiple mappings is NOT the issue (ofcourse IPs and ports differ). It just does NOT map TCP ports, only UDP

(net.upnp_tcp_only=true seems to help)

Miroslav

net.upnp_tcp_only ?

sorry, found it the same minute you replied

MP

It's a router bug, by the way. Your router overwrites the TCP mapping with the UDP one.