Outline · [ Standard ] · Linear+ Emule through socks5 proxy, UDP traffic problem

[Alya]

Computer configuration:
eMule Plus version:
Using proxy:	Don't know
Firewall:	Don't know
CPU:
Memory:
Operating System:
Updated drivers for network and video:	Don't know

I'm running eMule Plus through Socks5 proxy gateway.

I configured the proxy in Preferences/Connection options, indicated that it's Socks5, etc

Due to various strange problems (like search intermittently hanging) I decided to look at the traffic with a sniffer. The problem immediately became obvious:

Only TCP packets are being sent to proxy.

The UDP traffic is NOT sent to the proxy, even though it's Socks5 and fully supports UDP proxying.

Is this a huge bug? Or does eMule have incomplete Socks5 support by design?

And if eMule does not properly support Socks5 protocol, then why does it even allow to choose socks5 proxy?

In any case, I have a whole bunch of UDP packets going nowhere - how can I remedy this situation?

Sockifying eMule (with a program like SocksCap) doesn't work either...

Any suggestions?

[Aw3]

UDP is not used for proxy connections by design. Client can work without UDP.
Sending is pretty obvious, but is it possible to receive UDP packets through that type of proxy?

[Alya]

is it possible to receive UDP packets through that type of proxy?

Any properly implemented Socks5 server would proxy both the UDP traffic originating from my computer and the return UDP traffic coming back.

It will not proxy UDP traffic originating outside (ie UDP traffic from somebody to whom I never sent any UDP packets in the first place).

Good example to illustrate this difference would be VoIP softphone running SIP and RTP protocols (both are UDP):

Socks5 can proxy SIP packets to my VoIP provider and back, so softphone can carry out SIP-based tasks (such as registering with VoIP provider, etc) without a problem.

But RTP packets are not allowed to come through, so audio cannot be properly setup. That's why you cannot use an application that requires connection from outside (like a softphone) through Socks5 proxy.

Similarly, in case of eMule, the unsolicited UDP traffic from outside would not go through Socks5 proxy. But UDP traffic originating from my client would be proxied to destination and the return traffic (from same IP and port) would be allowed to come through. So as long as the other client/user isn't firewalled and allows me to initiate UDP traffic, the subsequent UDP exchange should work through Socks5 proxy.

[Aw3]

Similarly, in case of eMule, the unsolicited UDP traffic from outside would not go through Socks5 proxy. But UDP traffic originating from my client would be proxied to destination and the return traffic (from same IP and port) would be allowed to come through. So as long as the other client/user isn't firewalled and allows me to initiate UDP traffic, the subsequent UDP exchange should work through Socks5 proxy.

The thing is that UDP connection can be initiated from outside.

[DonGato]

It's better you disable UDP as you're not able to receive external packets, and that's is part of the protocol.

[Alya]

How can I disable UDP?

In Preferences -> Connection -> Clientport the checkbox "Disabled" (under the UDP port) is already marked.

Yet my sniffer shows that eMulePlus is still generating a lot of UDP traffic.

Is there another way to completely disable UDP?

[Aw3]

If it disabled, your client shouldn't do it by design. If it's doing that, you can send me a PM with captured packet content to check.