The problem discussed below is caused by routers (NAT, hardware or something else) and firewalls.

If you need to test your connection port, use this Soulseek port test

You've undoubtably just starting using Soulseek, or just had a change made to your internet connection, or possibly, you just got fed up with the connect difficulties.

For some *unknown* and extremely ^spooky^ reason, you've found that many people are unbrowseable on Soulseek and transfers often fail. While many of those may be users that only share to their Buddy-List, others just have improperly configured connections.

Some of them are helpless, if they are at a School, Business, or other location where they have no control over their internet connection. This might even fit your circumstance. In such case, there is nothing one can do.

But, if you are a home user with a Router that isn't configured for Soulseek, or a Firewall that blocks Soulseek, then you have a chance to fix it and get access to a lot more users.

If your router doesn't forward or allow access thru the default Soulseek port(s) 2234-2239 to the box your Soulseek client is running on, you will not be able to transfer to many of the users on Soulseek.

If both you and the other user have misconfigured routers, then you will not be able to transfer to or from them at all. Browsing will inevitably fail, transfers will die with "Connection failed" errors, and you will experience other difficulties.

So, to eliminate this problem you need to open or forward the port you're using from your router to your client box.

In this example, the remote user's Soulseek Port isn't accessible, but you can still transfer to and from via your open Soulseek Port.

With remote misconfigured routers, other users should be able to download from you. However, you may not be able to download from them without waiting a bit longer for connections to start and they may just timeout completely if you are unlucky or their configuration is really fascist.

If they timeout, just try again. (or complain :)

And let me put it another way: If your router isn't configured, only outgoing (not direct) connections work. Meaning that you may experience a lag while direct connections timeout and non-direct connections start.

If their router is misconfigured as well... neither of you can initiate an outgoing or incoming (direct) connection, and you can't transfer anything to each other.

If either one of you has a properly working router or no router (like dial-up), you'll be able to transfer files.

But, since many people have misconfigured routers, you need to open your Soulseek port.

Links:
My Soulseek Server and Client port tests
The Nicotine FAQ Item on the subject.