It was much simpler than my other thought. This is to prevent a malicious client from taking a server down by sending a large number of connection requests that it then aborts. Integrated code from Matthew Danish that allows the user to specify the port to use from the command line. Warnings from 0.3.0 still apply. Use with caution.
Spring is in the air, after all.
This is almost guaranteed not to work, as I've not tested it with clients that support the new features. There is a potential DOS attack against all versions, see the BUGS file. The REST in the RFC only applies to block or compressed mode transfer, which oftpd does not currently support. However, it appears that Unix systems interpret the parameter to the REST command as the offset into the file to resume from.