Originally Posted by BlurredD

It depends on what program or script you're using to see who's in the server. Many programmers reasonably assumed that servers would only host on port 10052, and as a result they hard-coded that port number into their code instead of parsing it from the server list. As a result, an attempt to join Zeal Duels, which is hosted on port 10058, may send you to Zeal Alpha, which is hosted on port 10052. JJ2+ now allows you to join servers hosted on ports other than 10052.