Wednesday, December 5, 2012

LAN Security

One of the main information that network administrator should have is how to secure his network, so this lesson will give a basic information about the LAN network security.


The Ethernet LAN has many security weaknesses when facing attacks externally and internally. Security measures must be taken to ensure an secured environment for communications ever the Ethernet LAN. The following are some key risks in an Ethernet LAN:

• The primary weakness with Ethernet is that it is a broadcast system . Every message sent out by any computer on an Ethernet LAN segment reaches all parts of that segment and potentially could be read by any computer on the segment. Sniffing type programs can record, read and analyze all the messages on a segment. Actually others can read your password and subsequently login to any account. They can also change the information and forge totally different messages.

• Peer-to-Peer networking systems (both Windows and Macintosh AppleTalk) for Workgroups allow people on the network to share files and printers, which open up your files to anyone using another computer in the group.

• Some applications, such as FTP program which allows you to get files from and send files to another computer, may have an option in their configuration which allow other computers to get into your computer and have access to your files while the program is running .

• Privileges of the operating system of a server in the Ethernet maybe incorrectly configured and users may have unintentional access to sensitive parts of the file store.

• If the NFS (Network File System) is deployed in an Ethernet LAN and the NFS part of a file store on a remote computer, the contents of the files can be snooped when reading or writing a file to the NFS drive.

• It is relatively easy in an Ethernet LAN to fake an Email message and other messages which purports to come from someone else. It is also possible to forge a login session by recording a legitimate one and running the recording later on.

There are many hardware and software solutions to address the above Ethernet LAN security issues:

Hardware Solutions for Ethernet LAN Security

• Use a switched network: A switch can segregate a network into many parts which can effectively preventing snooping and sniffing on a network. These switches also reduce network traffic by limiting messages to only the parts of the network on which they are needed to improve the efficiency of the whole network.

• Bridges and Routers: Bridges and routers are electronic filters which only pass a network message through themselves if the destination lies on the other side of the filter. Consequently if "the snooper" is on one side of a bridge or router they will not see any traffic passing between computers on the other side of the filter.

• LAN Security Architecture (LSA): a proprietary technique where twisted pair hubs inspect incoming messages and will only transmit them unscrambled to the destination computer. All other computers on the hub receive scrambled messages.

Software Solutions for Ethernet LAN Security

• Encryption: Encrypting the data passing between your computer and its destination. There are many encryption technologies and product available which effective protect information and data privacy. The popular encryption methods used are PGP (Pretty Good Privacy).

• Authentication: Use user name and password to authenticate users. It is necessary to encrypt the password and implement timestamps making forgery extremely difficult.

• Combination technologies: Many new technologies are available which doing both authentication and encryption. One of such technologies is Kerberos which uses tokens, timestamps, tickets and encryption to make transactions between computers secure.

Many network security technologies at the layer 3 (the network layer) can also be deployed to address the Layer 2 (Ethernet layer) security vulnebilities.



Now try to Answer these question to test your knowledge :

Give two hardware solutions for Ethernet LAN security.
Give two software solutions for Ethernet LAN security.

Please answer these question in a comment.


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