Friday, January 14, 2011

How to Troubleshoot LAN

Troubleshooting the local area network means identifying and removing the network problems for getting the optimized performance. In order to troubleshoot the problem in the LAN, it is important to monitor the LAN to identify the problems. LAN monitoring can be accomplished with the network management computer or general network sniffers. Protocol Analyzer provides various LAN troubleshooting solutions over the TCP/IP networks.

LAN/TCP/IP troubleshooting can often be tricky and the troubleshooting scenarios includes finding duplicate IP addresses on the network computers, misconfigured network applications, non-optimized network devices, low service performance, cabling problems, faulty LAN cards and network switches, viruses and spyware attacks, misconfigured firewall, security issues, DNS/DHCP problems, proxy server’s settings and overloading of the network servers with the number of software applications.

The problems in the Local Area Network can be aroused by a number of reasons as mention above. Being a LAN/Network administrator it’s your responsibility that you are well aware of your LAN infrastructure, network hardware, software, user access rights and preferences and the major configurations of the network. The best practice is to make inventory of all the resources of your LAN such as number of workstations, software installed and network hardware.

Following section provides the useful tips in diagnosing and troubleshooting the most common problems in your LAN. Whenever you face connectivity issues, security issues and performance issues the following tips are helpful in diagnosing troubleshooting the problems.

Connectivity Issues

  • First thing to check it to make sure that you have the same class IP address and the associated subnet mask in all the computers in your LAN.
  • Make sure that you have provided the accurate gateway address on all the computers.
  • Ensure that all the network cables are tightly plugged at both ends i.e. one end in the Hub/Switch and one in the LAN card.
  • Make sure that the lights on the Hub/Switch and LAN card are ON and working.
  • If you are behind a proxy server and facing internet connectivity issues, make sure that you have provided the accurate proxy server’s settings at the client computers.
  • Check your firewall settings and make sure that the firewall is not blocking the incoming and outgoing traffic.
  • Use the PING command at the common prompt to verify the connectivity with the other computer.


At command prompt

  • Ping and press enter ( is the IP address of the other computer)
  • If the connectivity issue is with the particular computer, reinstall the driver of the NIC adapter and if the problem is still there then change the NIC adapter and reconfigure it.
  • If the connectivity problem still not resolved then check the network cable from computer to HUB/Switch
 Security Issues

Security issues are more likely to occur in the LAN if no proper security mechanism, policies, antivirus programs and security methods have been implemented.
  • Install up-to-dated antivirus and anti spyware program and regularly scan your network server all the computers in the network.
  • In the proxy server block notorious applications that cause security issues in the network and define specific internet access rules for the users.
  • Use strong passwords, encryption methods and limit the access to the network resources.
  • Enable logging on all the network computers and server machine.
  • Implement security policies.
  • Update your operating system and install latest services packs and security patches.
  • Clean computer’s registry with the excellent Windows registry cleaner software. An optimized an error free registry is required for the smooth functioning of the computer.
  • Implement firewall on the gateway computer and it will save your computer from the unauthorized internal and external access.
The above tips will definitely help you out in resolving the security related issues in your LAN.

Performance Issues

The performance issues in the network occurs with the heavily installed applications, Windows registry errors, antivirus and anti spyware free systems, low or faulty hardware, low physical memory, unnecessary network shortcuts, simultaneous access to the server for the same resources and in the unmanaged network environment.
  • Dividing the network in the subnets is helpful in load balancing and improving the performance.
  • Remove unnecessary network shortcuts and it will increase the network browsing speed.
  • Clear cookies, browser’s history and other temporary files.
  • Increase the physical memory (RAM)
  • Uninstall any unnecessary software applications from computers.
  • Separately configure the proxy server, File server, Print server and Gateway computer to put the minimum load on each server.
  • Install the LAN cards that support 10/100 Mbps speed and use Switch instead of Hub in the LAN.
hopefully the above mentioned tips are helpful in resolving the most common connectivity, security and performance related issues in.