SELinux in Fedora 14 is configured to constrain the ports on which SSH can listen (see the bug report). The solution:
setsebool -P sshd_forward_ports 1
This allows SSH to listen on ports besides 22, and to forward ports. Reading the bug report is interesting. In my opinion, OpenSSH has an outstanding security track record, and we probably don’t need additional SELinux policy to constrain it. It’s probably wise to practice security in-depth (to have more than one line of defense), but it creates a large road bump for most SSH power users. From what I read, it sounds like most people still disable SELinux.