Connecting to FTP Server

[mosquito]

I have an FTP Server running (IIS 4 on WinNT Server 4.0 SP6 port 21). The server resides behind a small proxy with Sygate 3.1 (NAT translation) I opened port 4567 on the sygate machine, and routed it to port 21 on the IIS box.

• When I try to connect locally (from within the network) everything works ok.
• When I connect from outside the company (with a dail-up over internet) everything works ok.
• But when I connect from the other site of the company (other lan, other location), I receive an "500 invalid port" error when retrieving the directory list. I'm connected, and I show up in the connected users list on the IIS machine. That network is shielded by a Sygate 3.1 proxy and an ADSL router.

Is it possible that the router is blocking the client ports required to do the FTP?

I tried it with ftp, Leechftp, CuteFTP and telnet, and they all give me the same result.

I'm stomped here, so if you could give me a hint?

(found the ftp commands on http://www.cis.ohio-state.edu/htbin/rfc/rfc959.html)

thx a lot.

[Dave22]

Is the Sygate machine set up with the same mappings as the one that works? I'm not familiar w/ Sygate, but are there any packet filtering rules between the FTP server and that remote network?

Have you tried using PASV mode on the FTP client?

[mosquito]

I'll check the PASV mode. The rest seems ok.