- \n
- Identify the problem<\/strong>: Understand the issue and gather relevant information.<\/li>\n\n\n\n
- Develop a theory<\/strong>: Create a working hypothesis based on the gathered data.<\/li>\n\n\n\n
- Test the theory<\/strong>: Use tools like ping, tracert, and DNS checks.<\/li>\n\n\n\n
- Plan of action<\/strong>: Determine the steps needed to resolve the issue.<\/li>\n\n\n\n
- Implement the solution<\/strong>: Apply the chosen solution.<\/li>\n\n\n\n
- Verify system functionality<\/strong>: Ensure the problem is resolved.<\/li>\n\n\n\n
- Document the issue<\/strong>: Record findings for future reference.<\/li>\n<\/ol>\n\n\n\n
<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.balajibandi.com\/wp-content\/uploads\/2019\/05\/image-1.png\")
<\/figure>\n\n\n\n1. Identify the Problem<\/h3>\n\n\n\n
The first step in troubleshooting a network is to identify the problem. As a part of this step, you should do the following:<\/p>\n\n\n\n
- \n
- Gather information<\/strong> about the current state of the network using the network troubleshooting tools that you have available to you.<\/li>\n\n\n\n
- Duplicate the problem<\/strong> on a test piece of hardware or software, if possible. This can help you to confirm where your problem lies.<\/li>\n\n\n\n
- Question users<\/strong> on the network to learn about the errors or difficulties they have encountered.<\/li>\n\n\n\n
- Identify the symptoms<\/strong> of the network outage. For example, do they include complete loss of network connection? Slow behavior on the network? Is there a network-wide problem, or are the issues only being experienced by one user?<\/li>\n\n\n\n
- Determine if anything has changed<\/strong> in the network before the issues appeared. Is there a new piece of hardware that\u2019s in use? Has the network taken on new users? Has there been a software update or change somewhere in the network?<\/li>\n\n\n\n
- Define individual problems clearly<\/strong>. Sometimes a network can have multiple problems. This is the time to identify each individual issue so that your solutions to one aren\u2019t bogged down by other unsolved problems.<\/li>\n<\/ul>\n\n\n\n
2. Develop a Theory<\/h3>\n\n\n\n
Once you have finished gathering all the information that you can about the network issue or issues, it\u2019s time to develop a working theory. While you\u2019re producing your theory about the causes of the network issue, don\u2019t be afraid to question the obvious, but remain on the lookout for more serious issues. Sometimes a network outage occurs because someone tripped on a wire or some other simple problem. <\/p>\n\n\n\n
3. Test the Theory<\/h3>\n\n\n\n
Using the tools at your disposal, it\u2019s time to test your theory. If your theory is that the network router is defective, try replacing it with another router to see if that fixes the issue. At this stage, it\u2019s important to remember that proving your own theories wrong doesn\u2019t mean that you\u2019ve failed. Instead, it means that it\u2019s time to return to step two, develop a new theory, and then find a way to test that one. Sometimes your first theory may be right, but it\u2019s also common to go through several theories before arriving at the true cause of your network\u2019s issues.<\/p>\n\n\n\n
4. Plan of Action<\/h3>\n\n\n\n
Once you\u2019ve confirmed your theory about the causes of the network issues, you\u2019re in a position to solve them. Come up with a plan of action to address the problem. Sometimes your plan will include just one step. For example, restart the router. In other cases, your plan will be more complex and take longer, such as when you need to order a new part or roll a piece of software back to a previous version on multiple users\u2019 computers.<\/p>\n\n\n\n
5. Implement the Solution or fix.<\/h3>\n\n\n\n
Now that you have a plan for fixing the network, it\u2019s time to implement it. There are some solutions that you may be able to do by yourself, while others may require cooperation from other network administrators or users.<\/p>\n\n\n\n
6. Verify System Functionality<\/h3>\n\n\n\n
Once you\u2019ve implemented your solution, be sure to test the network. Make sure that the issue in question has been resolved, but also be on the lookout for other issues that may have arisen from the changes that you made to the network. As part of your verification process, make sure to consult both the network tools at your disposal as well as individual user accounts of their experiences on the network.<\/p>\n\n\n\n
7. Document the Issue and Monitor<\/h3>\n\n\n\n
If you are a network professional or an enthusiast who is around networks often, then it\u2019s safe to say that this won\u2019t be the last time you encounter this particular issue. Make sure to document each stage of troubleshooting the problem, including the symptoms that appeared on the network, the theory you developed, your strategy for testing the theory and the solution that you came up with to solve the issue. Even if you don\u2019t reference this documentation, it may be helpful to another network engineer at your company in the future and could help to shorten network downtime.<\/p>\n\n\n\n
Network Troubleshooting Tools<\/h2>\n\n\n\n
Command-Line Tools<\/h3>\n\n\n\n
<\/p>\n\n\n\n
- \n
- ping <\/strong>\u2014 A TCP\/IP utility that transmits a datagram to another host, specified in the command. If the network is functioning properly, the receiving host returns the datagram.<\/li>\n\n\n\n
- tracert\/traceroute<\/strong> \u2014A TCP\/IP utility that determines the route data takes to get to a particular destination. This tool can help you to determine where you are losing packets in the network, helping to identify problems.<\/li>\n\n\n\n
- nslookup <\/strong>\u2014 A DNS utility that displays the IP address of a hostname or vice versa. This tool is useful for identifying problems involving DNS name resolution.<\/li>\n\n\n\n
- ipconfig <\/strong>\u2014 A Windows TCP\/IP utility that verifies network settings and connections. It can tell you a host\u2019s IP address, subnet mask and default gateway, alongside other important network information.<\/li>\n\n\n\n
- ifconfig <\/strong>\u2014 A Linux or UNIX TCP\/IP utility that displays the current network interface configuration and enables you to assign an IP address to a network interface. Like ipconfig on Windows, this command will tell you vital information about the network and its status.<\/li>\n\n\n\n
- netstat <\/strong>\u2014 A utility that shows the status of each active network connection. This tool is useful for finding out what services are running on a particular system.<\/li>\n\n\n\n
- tcpdump \/ Wireshark <\/strong>\u2014 A utility that is used to obtain packet information from a query string sent to the network interface.<\/li>\n\n\n\n
- nmap <\/strong>\u2014 A utility that can scan the entire network for various ports and the services that are running on them. You can use it to monitor remote network connections and get specific information about the network.<\/li>\n\n\n\n
- route <\/strong>\u2014 A command that enables manual updating of the routing table. It can be used to troubleshoot static routing problems in a network.<\/li>\n\n\n\n
- arp <\/strong>\u2014 A utility that supports the Address Resolution Protocol (ARP) service of the TCP\/IP protocol suite. It lets the network admin view the ARP cache and add or delete cache entries. It can be used to address problems having to do with specific connections between a workstation and a host.<\/li>\n\n\n\n
- pstools<\/strong> – from MS this useful tools.<\/li>\n<\/ul>\n\n\n\n
Network Troubleshooting Applications<\/h3>\n\n\n\n
In addition to command-line tools, there are also a number of standalone applications that can be used to determine the status of a network and to troubleshoot issues. Some of these applications may be included in the system that you are working with, while others may need to be installed separately.<\/p>\n\n\n\n
- \n
- Packet Sniffer<\/strong> \u2014 Provides a comprehensive view of a given network. You can use this application to analyze traffic on the network, figure out which ports are open and identify network vulnerabilities.<\/li>\n\n\n\n
- Port Scanner <\/strong>\u2014 Looks for open ports on the target device and gathers information, including whether the port is open or closed, what services are running on a given port and information about the operating system on that machine. This application can be used to figure out which ports are in use and identify points in a network that could be vulnerable to outside attacks.<\/li>\n\n\n\n
- Protocol Analyzer<\/strong> \u2014 Integrates diagnostic and reporting capabilities to provide a comprehensive view of an organization’s network. You can use analyzers to troubleshoot network problems and detect intrusions into your network.<\/li>\n\n\n\n
- Wi-Fi Analyzer<\/strong> \u2014 Detects devices and points of interference in a Wi-Fi signal. This tool can help you to troubleshoot issues in network connectivity over a wireless network.<\/li>\n\n\n\n
- Bandwidth Speed Tester<\/strong> (fast.com or google fiber speed test) \u2014 Tests the bandwidth and latency of a user\u2019s internet connection. This application is typically accessed through a third-party website and can be used to confirm user reports about slow connections or download speeds.<\/li>\n<\/ul>\n\n\n\n
Network Hardware Troubleshooting <\/h3>\n\n\n\n
<\/p>\n\n\n\n
- \n
- Cable replace<\/strong> – this may be Copper or Fiber – to avoid any Physical cable issues around.<\/li>\n\n\n\n
- Swap the SFP<\/strong>, this may Copper to Fiber SFP Module to identify the issue.<\/li>\n\n\n\n
- Check with another device (like a PC or Handheld device).<\/li>\n<\/ul>\n\n\n\n
Happy Labbbing…………………!<\/p>\n","protected":false},"excerpt":{"rendered":"
Network troubleshooting methodology involves the following steps 1. Identify the Problem The first step in troubleshooting a network is to identify the problem. As a part of this step, you should do the following: 2. Develop a Theory Once you have finished gathering all the information that you can about the network issue or issues, […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2,7,27],"tags":[],"class_list":["post-2441","post","type-post","status-publish","format-standard","hentry","category-cisco","category-linux","category-tools"],"_links":{"self":[{"href":"https:\/\/www.balajibandi.com\/index.php?rest_route=\/wp\/v2\/posts\/2441","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.balajibandi.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.balajibandi.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.balajibandi.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.balajibandi.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2441"}],"version-history":[{"count":3,"href":"https:\/\/www.balajibandi.com\/index.php?rest_route=\/wp\/v2\/posts\/2441\/revisions"}],"predecessor-version":[{"id":2623,"href":"https:\/\/www.balajibandi.com\/index.php?rest_route=\/wp\/v2\/posts\/2441\/revisions\/2623"}],"wp:attachment":[{"href":"https:\/\/www.balajibandi.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2441"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.balajibandi.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2441"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.balajibandi.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2441"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
- Swap the SFP<\/strong>, this may Copper to Fiber SFP Module to identify the issue.<\/li>\n\n\n\n
- Port Scanner <\/strong>\u2014 Looks for open ports on the target device and gathers information, including whether the port is open or closed, what services are running on a given port and information about the operating system on that machine. This application can be used to figure out which ports are in use and identify points in a network that could be vulnerable to outside attacks.<\/li>\n\n\n\n
- tracert\/traceroute<\/strong> \u2014A TCP\/IP utility that determines the route data takes to get to a particular destination. This tool can help you to determine where you are losing packets in the network, helping to identify problems.<\/li>\n\n\n\n
- Duplicate the problem<\/strong> on a test piece of hardware or software, if possible. This can help you to confirm where your problem lies.<\/li>\n\n\n\n
- Develop a theory<\/strong>: Create a working hypothesis based on the gathered data.<\/li>\n\n\n\n