squid and ftp
 

running squid without any problem, can access from clients ftp sites.
e.g
ftp://ftp.microsoft.com

but unable to connect a windows ftp server , ftp://mnauman.com from clients, but able to open it from server. there isn't any firewall restriction. but getting connection timeout, unable to solve problem. any one know about this error, i think this is about active or passive ftp problem, but how to solve this one.
thanks