Despite The Best Efforts To Maintain the network’s stability and performance, certain events sometimes occur that disrupt the network’s Normal Operation.

This article examines common network problems and offers tips for quickly resolving them and preventing future issues.

Common Network Problems

1. Duplicate IP addresses

When two devices try to share a single IP address, they see that the address is already in use and cannot connect to the network.

Solution: The cause of this problem is the DHCP router’s default configuration. DHCP is probably trying to assign an address to your new device at the beginning of the subnet. In contrast, another device may have already used these addresses as static IP addresses.

Reviewing the DHCP server may not be a bad idea if you have just introduced a new device or server to your network. To do so, you just have to disable the DHCP server, disconnect the devices from the web, enable DHCP again, and connect the devices to the network.

Precautions: By changing your router’s configuration to start assigning DHCP addresses near the end of the subnet, you can take a simple step to prevent IP address interference and reserve lower addresses for devices that require a fixed IP address.

2. IP address unavailable

To solve this problem, you must use the ipconfig command if a workstation or device on the network has an IP address that starts with 169. xxx means that no IP address is available from the DHCP server to be assigned to the client.

Solution: Users with cable internet who do not have a local router will receive limited IP addresses directly from the ISP. The authorized IP addresses assigned by the service provider may have expired. To solve this problem, you have to buy a router or use mobile Internet to get a unique IP address.

In this case, you have a set of local addresses that devices on the local network can use without running out.

If you already have a local DHCP router, your network’s default address may be too small. To solve this problem, go to the router’s DHCP settings, check the DHCP address range, and adjust it to your network needs.

Precautions: Every network connected to the Internet must have a local router that supports NAT and DHCP to avoid security issues and address shortages. The router should be the only device connected to the modem, and all other appliances should connect to the network through the router.

3. DNS problems

DNS configuration problems can usually cause errors such as network path not found, IP address not found, or DNS name missing. The nslookup command-line tool can be used to view the DNS settings of workstations or clients quickly.

Solution: Workstations and other network devices can be configured to use their DNS servers, regardless of the DHCP-designated server.

To do this, you must check the Internet Protocol Version 4 (TCP/IP) settings of your adapter to ensure that the DNS server is not misconfigured, and set it to Obtain DNS server address.

Preventive Solution: Your local router may be configured to act as a DNS server and obtain a DNS through ISP servers. Change your network DHCP settings to access DNS servers directly.

4. A workstation is unable to connect to the network

Suppose only one workstation displays a “No Internet” message when you open a web browser. In that case, we should assume that other network equipment and components are safe and focus on the hardware and software that displayed the message.

Solution: To resolve this network issue, check for factors that caused the connection to be lost, such as a cable issue, a weak WiFi signal, a network card failure, or incorrectly installed drivers. Ensure the workstation’s network adapter is configured correctly with an IP address, subnet mask, and DNS servers.

If this does not resolve the issue, check the device’s firewall software to ensure that the required ports on the external network are open. Standard ports include 80 and 443 for web traffic, 25, 587, 465, 110, and 995 for email.

Precautions: It is usually best to set all workstations’ TCP/IP settings to automatically assigned. Use a DHCP server to provide a uniform configuration to all devices on the network. Most DHCP servers support static IP mapping when a static IP is required for a particular workstation or server.

5. Cannot connect to Local File or Printer Shares

Sharing problems are among the most challenging network problems because they involve a large number of components that must be appropriately configured.

Conflicts in mixed security environments often lead to sharing issues. Even within a single operating system version, security models can differ slightly, making it challenging to connect workstations.

Solution: We can solve the sharing problems in the best way by examining the probabilities in the following order

Make sure the required services are running. The server, TCP/IP NetBIOS Helper, workstation, and browser-related services must all run on Windows. Samba is a crucial component for sharing with Windows systems on Linux machines.

Check your firewalls. It is widespread for a workstation firewall to be configured to block file and printer-sharing traffic, especially if a new antivirus package is installed that introduces itself as a firewall. Firewall problems can also exist at the hardware level, so make sure routers or switches manage shared traffic on the subnet.

Make sure all workstations are on the same subnet.

This problem usually occurs only in complex networks. However, even simple networks sometimes have fixed IP equipment with inadequate subnets. The result is that external traffic is well transmitted, while internal traffic encounters unexpected obstacles.

All Windows network adapters require File and Printer Sharing for Microsoft Networks, Client for Microsoft Networks, and NetBIOS over TCP/IP enabled.

Once you have reviewed everything, the permissions are another critical factor that causes this problem. Several layers of the Windows operating system allow access to resources, and each has its own user interface:

• Examine systems that are configured with the wrong workgroup or domain.
• Make sure HomeGroup is configured correctly.
• The network type is set to Public.
• NTFS permissions are not misconfigured.

6. The local network is not able to connect to the Internet

This condition can be intermittent or continuous. Often, the hardest part is investigating a problem with an external network. Such a problem may sometimes force organizations to turn to other Internet service providers.

Solution: The first step is to restart the router and modem. Next, the Tracert tool can be used to identify communication interruptions. If necessary, take a screenshot and share it with your ISP.

Preventive action: The best solution is to ensure you get an internet connection from a first-class service provider. Some companies act as intermediaries, receiving the Internet from the first companies and providing it to you. So, getting a stable internet connection would help eliminate as many intermediaries as possible.

7. Slow internet performance

Slow performance is usually caused by congestion or by poor-quality connections, which can lead to slow speeds or sudden outages. This problem is mainly seen in leased lines where dedicated bandwidth is provided. Congestion may not be directly related to bandwidth reduction, as only one port on a switch or router can cause network performance to degrade.

Solution: For speed testing, use active websites to run tests via remote servers across different geographic regions. The above approach can identify congested areas in the ISP network.

DNS servers are among the most critical components of the Internet and are often overlooked. Misconfigured DNS servers can cause routing congestion or load-balancing issues. While you typically use your DNS ISP settings, they may redirect traffic through overloaded web caches. You can temporarily configure your DNS settings to use OpenDNS.

Preventive action: If Internet operation is critical, you must provide various communication mechanisms. For example, give a combination of ADSL, VDSL, mobile, or fiber-optic Internet so you can quickly switch to another option when needed and when the network is down. The above method indeed increases costs, but you can be sure you can easily use the alternative option in case of poor network performance.

A local DSL operator may offer improved reliability at a slightly higher cost, but for consistent performance, your organization may need an expensive leased line.

FAQ