ftp problems in masquerading with WIN box

["Bill" <bill@willco.org>]

Hi all,
        I have a Debian box (woody) with IP Masq set-up, no problems with
accessing the internet or internally with ftp with my win98 and win2000
box's
but if I try to access external ftp sites it logs in, authenticates and then
gives the following error

< 500 Illegal PORT command.
* PORT command failed

Any ideas on what I've set wrong or haven't set would be greatly appreciated

ftp straight from Debian box works fine, but it is used as a router only at
this stage, no GUI installed.

Thanks in advance
    Bill

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