Hi,
Network Sec occurs at all TCP/IP layers ie Physical layer security will deal with cable shielding, quantum cryptography, burglar proofing,CCTV, Proxy card and Biometric door access control systems, all in the name of protecting the physical network infrasructure.

The Data link and MAC layers will deal with security at the frame level, which means security aware switches bridges, and wireless security, such that you just dont come and plug your cable into the switch and start pinging all nearby computers.

At the Network layer, you are dealing with exiting the local switch-workstation-server,network to another network having its own switches, workstations and servers. Here, you have routers and you are actually dealing with how each router vendor incorporates security into his products.

At the transport layer, you are dealing with application programming using sockets and ports so your program can talk to another program out there on another network, you have security libraries built into programming language compilers so your program is end to end secure.

At the application layer, you will find the usual network applications like Email,WWW,Multimedia, Database servers like DB2, File servers, and System managers like SMS.

In all these layers, the following security algorithms are in common use, so you need to assess the network layer you are working in and then find the appropriate algorithm. Standards set up by ISO,ITU-T,IEEE and IETF bodies for security in each layer will usually be of vital help ie IPSec for Network layer security,SSL for application and transport layer security, WEP for wireless security though not secure anymore than the RC4 algorithm it was based on, GSM security for mobile phones though also not secure than the A5/1 algorithm it was based on and other standards too are available.

There are two basic algorithms in Network security ie Symmetric key algorithms and Public key algorithms.
In the former you have DES,Triple DES,Twofish,Blowfish,RC5,IDEA, etc
In the latter RSA is mainly used.

Network security is a wide study, but i hope you find this useful.

Network security starts from authenticating any user. Once authenticated, firewall enforces access policies such as what services are allowed to be accessed by the network users. Though effective to prevent unauthorized access, this component fails to check potentially harmful contents such as computer worms being transmitted over the network. An intrusion prevention system (IPS) helps detect and prevent such malware. IPS also monitors for suspicious network traffic for contents, volume and anomalies to protect the network from attacks such as denial of service. Communication between two hosts using the network could be encrypted to maintain privacy. Individual events occurring on the network could be tracked for audit purposes and for a later high level analysis.

Wide-area networks also operate over a variety of wireless media. There are 4 steps to creating a network
1.Choose your wireless equipment
2.Connect your wireless router
3.Configure your wireless router
4.Connect your computers

And as said by kawalya, Network security is a vast subject.

hey all,
i'm planning to do a project on network security...
can u'll tel me d prerequisite languages i need to know...
and how should i start of n go bout d project?
can u'll pls give me a brief description of d project details...

Hi, you can fall in one of a no. of categories of projects ie develop a new security algorithm which you can later code into a program library, develop a secure network application, or develop code to break into an existing secure system and render it insecure.

The good languages i would recommend are those that a strongly typed like Java, but also C is very handy and powerful despite its weak typing.

Which ever your choice is: we will pick on from there later.

Thanx.

Thanks for the post...

Can u please help me in where should i start as i am planning to go for Security Certification.
I do have a CCNA..cleared in dec 06.

Any help would be appreciated..

i've to do the project in network security....
can u tell me tne languages and the mothod of doing project in network security

Hi, the methodology will always remain the same ie problem identification, research study into the prob, analysis, generating solutions, choosing optimal solution, implementing the optimal solution, testing and evaluating the implemented solution, system hand over, and finally provide ongoing support and maintenance of your solution.

The above, applied to computer programming means that you will have to draw some diagrams that look like boxes at each phase, and use some language to explain those boxes to the computers.

So far, java seems to explain those boxes very well.

Will pick on from there.