Im working with a Cisco 1841 Series Router Version 12.4. Im trying to get some rules setup to allow FTP access to our GlobalScape EFT 6.0.1 server via the Internet. I think the problem at this point is the router not opening passive ports needed when accessing through a browser window such as Explorer or IE. Access works perfectly internally but when trying to access from the www I get a prompt for credentials then the session times out during/after authentication. Here are the rules I have created so far. Any ideas what is missing? Thank you in advance for any assistance.
ip nat inside source static tcp 10.10.1.2 20 12.x.x.x 20 extendable
ip nat inside source static tcp 10.10.1.2 21 12.x.x.x 21 extendable
access-list 100 permit ip 10.10.1.0 0.0.0.255 any
access-list 100 permit tcp 10.10.1.0 0.0.0.255 any
access-list 110 permit tcp any host 12.x.x.x eq ftp
access-list 110 permit tcp any host 12.x.x.x eq ftp-data