I have finished setting up firewall for our DMZ. I placed first windows server behind the firewall for testing. I can access all ports on the firewall and ports which are being forwarded to my DMZ. I can access to FTP server on windows server too, when client computer is behind firewall it will connect but fail with the following error messages:
257 "/username" is current directory.
Host type (S): Microsoft NT
200 PORT command successful.
150 Opening ASCII mode data connection for /bin/ls.
! Timer cancelled blocking call
! Accept error: Blocking call cancelled
! Retrieve of folder listing failed (0)
Please note I have tried enabling and disabling passive transfers. The same time client server can connect servers on unprotected network.
I am using Linux and iptables to protect my network.
Thanks a lot!