In MacSSH, pull down the Favorites menu and select Edit Favorites... like this:
Then select your yip.org Favorite and click "Change" or press command-E. Go into the Security tab, and ensure that the Protocol: pulldown is set to ssh2 (Secure Shell). Then put this text in the lsh arguments: or Command: field, depending on what version you're using:
-L21:yip.org:21
If you already have another port forward in there, separate the above text from it with a space.
You may have to restart your ssh program after adding the tunnel. Screenshots coming soon.
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