Hello,
I am looking for an open source web based network traffic manager like Kerio(it is for windows) for Linux may be you didn't work with Kerio so I illustrate what I want:
I want to install it on my linux server that I want to use as my internet gateway and
monitor and log all users Internet traffic (not deeply packet and packet header monitoring like wireshark, I just want to see each user or IP, requests for which website or ip).
bandwidth manager for defined users or IPs (do not let to others, those whom did not defined in its database to access to Internet or server) .
NAT manager for IP and PORT mapping activities .
firewall to limit each user or PC(IP) to access or not to access some defined ports or services.
manage each NICs traffic as defined .
manage defined VPN's (kerio has its own VPN ).
be capable to add any feature to it .


Thanks for any help and suggestion.

I was about to give some suggestions, but I recalled seeing a really big list on the internet.

http://www.slac.stanford.edu/xorg/nmtf/nmtf-tools.html

Good luck, I hope you find something to suit your needs.

thanks but would you please give me a suggestion from this long list .

To each his own; I have worked with a few, and I don not have a favorite. Either get an answer from someone else, or just try a few out and pick your own. Good luck man!

see I want something like this : http://www.kerio.com/control that has:
Full Web Administration
Protect against evolving threats with application layer firewall, anti-virus protection and P2P Eliminator.

Control user Internet activity and productivity with user-based policies, Internet monitoring and web content filtering.
* Integrate with Active Directory for simplified password management.
* Monitor and restrict Internet access based on user login.
* View and print individual Internet activity, down to the search engine keywords.
* Identify bandwidth bottlenecks and Internet abuse.
* Minimize liabilities and prevent data leakage and harmful downloads from peer-to-peer (P2P) networks.
* Utilize multiple technologies including port blocking, payload analysis and behavior analysis to adapt to evolving P2P applications.
bandwidth efficiency and availability with link load balancing, bandwidth limiter, and connection failover.
* Expand network bandwidth by combining multiple Internet connections.
* Increase upload and download speeds.
* Improve the performance of high bandwidth services, such as VoIP or video conferencing.
* Set daily or monthly bandwidth usage quotas for individuals.
* Limit bandwidth on non-critical applications.
* Maintain connectivity for critical applications (email, SQL, web)
* Automatically switch to a second Internet connection in event of an Internet connection outage.
Unified Security
* Signature based packet analysis
* IP blacklisting
* Rule management
* Corporate level criteria - enforces default security policy immediately after installation
* Secure access remote administration - all changes to security policy are logged
* Create inbound and outbound traffic policies.
* Protect servers without the need for a DMZ through application-friendly NAT traversal.
* Perform stateful packet and protocol inspection and logging.
* Filter viruses and worms from incoming and outgoing traffic.
* Simplify deployment with integrated Sophos engine.
* Dual anti-virus ready for extra protection.
* Block access to websites with harmful or inappropriate content
* Apply categorization to traffic statistics
* Mac, Windows, and Linux VPN clients
* Clientless SSL-VPN for Windows networks

Log or restrict access to users based on:
* Group policy
* Time of day
* User status
* User location
View Web traffic usage by content category

but most of them that I read in list are just traffic analyzer and network performance analyzer.

I found one that I think it is good for others.
http://www.zentyal.com
but it works fine just with ubuntu 10.04 LTS I don't know why!!!!!!!!!!