Passive mode with wu-ftpd

[Bob Nielsen <nielsen@oz.net>]

I am running a wu-ftpd server on a machine inside my NAT
router/firewall, which uses ipmasq and ipchains.  I have port 21
forwarded from the firewall to the ftp server with ipmasqadm.

Retrieving files without using passive mode works fine from either
inside or outside the firewall.  From another host on my LAN, passive
mode also works.  However, from outside the lan using passive mode, the
connection freezes after the server sends the following:

        227 Entering Passive Mode (192,168,2,2,68,60)

I don't know if it is relevant, but found the following in
/usr/share/doc/wu-ftpd/wu-ftpd-faq.txt.gz:

    14. Normal ftp clients work, Netscape ftp's fail. So, passive
            mode doesn't work.
            Apparantly ftpd needs write permission on ~ftp/dev/tcp in
            order to operate correctly in passive mode (Solaris). Set it
            to the same mode as permissions shown by ls -lL /dev/tcp,
            being 666. Also read the Solaris man page for ftpd for
            Solaris-specific information. Changed from previous versions
            Fix:
cd ~ftp/dev
chmod 666 tcp

Is there an equivalent fix for Debian Linux, which doesn't have
~ftp/dev/tcp?

Or is this is a firewall configuration problem, in which case what
changes do I need to make there?  The fact that the server is sending
its 192.168.2.2 address makes me suspicious, since that is not
routable.

Bob