I have my FreeBSD working as a NAT router for my home network, so I use my Windows machine as my primary machine and connect to the internet through the FreeBSD machine.

Now whilst this setup is fine for accessing services such as http, pop and smtp from the masqueraded client, I cannot access FTP services consistently. By consistently I mean to say that I can access some FTP servers OK (upload and download is fine), but with some others I cannot - the aliased ftp client connects to the remote ftp server, but then fails to retrieve a directory listing on it.

Presently I am using a PPP connection, using the following /etc/ppp/ppp.conf settings:

# the next uncommented line indicates that NAT should be used:
nat enable yes

# the next uncommented line indicates that the NAT engine
# should use sockets (ensures FTP ok):
nat use_sockets yes
which I thought had resolved the problem since it works ok on some ftp servers, as mentioned above. However on other ftp servers it does not allow me access from the aliased ftp client. Is this an ftp client configuration issue (anything to do with the transfer mode 'PASSIVE/ACTIVE')?

Regardless of the fact I'm using PPP, what would be the preferred option for correctly routing ftp transfers to/from the masqueraded client (I'd really rather not do it using PPP to masquerade clients on the LAN)? Should I begin to look at ipf or another filtering package to address my NAT requirements?

Thanks in advance,
Jez