FTP and Masquerading

[Pascal Hambourg]

Hello,

Syed AbuBakr a écrit :
> I am  new to linux and need some guidance.

http://www.netfilter.org/documentation/index.html#documentation-howto

> PROBLEM:
> FTP is not working. My internal users can not connect external ftp and
> vice versa.

See the NAT HOWTO section, § "7. Special Protocols".
Try to load the FTP connection tracking and NAT helper modules :
# modprobe ip_conntrack_ftp
# modprobe ip_nat_ftp

If it still does not work, you'll have to give more details.
What exactly in FTP does not work and how do you see it does not work ?
- Establish a control connection ?
- Download files (including directory listing) ?
- Upload files ?
- Passive mode, active mode ?
Are you internal users set up explicitly to use the proxy for FTP ?

> SCENARIO:
> 1. I am using SQUID for proxy services.

Which services ? HTTP only or also FTP ?

> 2. OS is FedoraCore 5
> 3. Using transparent proxy

Squid will do transparent proxy only for HTTP, so that should not 
concern FTP.

> 4. Masquerading my out bound traffic.
> 5. All packages including kernel are same as they come with the
> standard distro of FC-5
> 6. Install time Firewall is disabled, so i have only a couple of rules
> in my ip tables.

Which rules ? You can list them with the command 'iptables-save'.

> I dont know how to recompile kernel or insert modules, So please do me
> a favour and give me a step by step how to of it.

Hopefully you don't need to recompile anything. And there is no step by 
step procedure unless you give *full* information about your setup.