Re: Connecting to FTP server through Winroute

From: Bargepole (
Date: 09/13/02

From: "Bargepole" <>
Date: Fri, 13 Sep 2002 09:01:40 -0400

"Danial Bennett" <> wrote in message
> I am having problems connecting to an ftp server through my local
> winroute pro 4 machine. I am in contact daily with the administrator
> of this server and he has noted that he is behind a firewall but has
> had no problem connecting to it from other sites except one. I
> previously was able to connect to the same FTP before the
> administrator installed a different firewall. This FTP is on the
> standard port(21) and also uses MD5 (whatever that really means). The
> problem is that I cannot get a list of the content and eventually get
> a socket error. I do technically connect to the server and can
> actually get messages from SYSOP to verify connection. I have read a
> few posts that mention NAT..I am not familiar with a lot of these
> terms just yet (at least not enough to be 100% comfortable). Winroute
> on my end is basically only forwarding ports, DHCP, and acting as DNS.
> Any help would be greatly appreciated.

You may be required to force your FTP client to use the alternate mode to
the one you're using now. Depending on how the FTP server's network firewall
is configured or its capability, it may not allow the server to initiate
outbound connections, defeating PORT mode. Or, it may not perform adequate
stateful packet inspection, inhibiting inbound connections to the server
specified data port, thereby defeating PASV mode.

Try changing your FTP client to use PASV mode if you're now using PORT mode
for that site (or vice versa). If your client can't readily be forced to
specify a mode (like Internet Explorer), try a different client.

If, after changing the mode specified, you still can't connect and operate
on the server, there's probably a packet filter rule in Winroute that now
blocks the FTP traffic. For example, if you were successfully using PORT
mode before and switched your FTP client to force the FTP server to use PASV
mode, a Winroute packet filter rule that blocks all incoming SYN packets
would kill the FTP functionality.

As long as the FTP server's command port is TCP port 21, Winroute's stateful
inspection will automatically allow any client FTP communication from your
network to a server by default. You don't have to worry about port mappings.
However, you must be sure your packet filter rules allow the type of
communications you expect.

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