Can troubleshooting tools

The TrafficDirector advanced packet filters let users monitor all seven layers of network traffic. The TrafficDirector multilayer traffic summary provides a quick, high-level assessment of network loading and protocol distributions. Network managers then "zoom in" on a specific segment, ring, switch port, or trunk link and apply real-time analysis and diagnostic tools to view hosts, conversations, and packet captures. TrafficDirector threshold monitoring enables users to implement a proactive management environment.

When these thresholds are exceeded, traps are sent to the appropriate management station to notify the network administrator of an impending problem. VlanDirector offers the following features for network administrators:.

In many situations, third-party diagnostic tools can be more useful than commands that are integrated into the router. For example, enabling a processor-intensive debug command can be disastrous in an environment experiencing excessively high traffic levels. However, attaching a network analyzer to the suspect network is less intrusive and is more likely to yield useful information without interrupting the operation of the router.

The following are some typical third-party troubleshooting tools used for troubleshooting internetworks:. Volt-ohm meters and digital multimeters are at the lower end of the spectrum of cable-testing tools. These devices measure parameters such as AC and DC voltage, current, resistance, capacitance, and cable continuity.

They are used to check physical connectivity. Cable testers scanners also enable you to check physical connectivity. A given cable tester might be capable of performing any of the following functions:. Similar testing equipment is available for fiber-optic cable. Because of the relatively high cost of this cable and its installation, fiber-optic cable should be tested both before installation on-the-reel testing and after installation.

Continuity testing of the fiber requires either a visible light source or a reflectometer. Light sources capable of providing light at the three predominant wavelengths— nanometers nm , nm, and nm—are used with power meters that can measure the same wavelengths and test attenuation and return loss in the fiber.

At the top end of the cable testing spectrum are TDRs. These devices can quickly locate open and short circuits, crimps, kinks, sharp bends, impedance mismatches, and other defects in metallic cables. A TDR works by bouncing a signal off the end of the cable. Opens, shorts, and other problems reflect the signal back at different amplitudes, depending on the problem.

A TDR measures how much time it takes for the signal to reflect and calculates the distance to a fault in the cable. TDRs can also be used to measure the length of a cable. Some TDRs can also calculate the propagation rate based on a configured cable length.

Fiber-optic measurement is performed by an OTDR. OTDRs can accurately measure the length of the fiber, locate cable breaks, measure the fiber attenuation, and measure splice or connector losses. An OTDR can be used to take the signature of a particular installation, noting attenuation and splice losses.

This baseline measurement can then be compared with future signatures when a problem in the system is suspected. These devices can monitor data line conditions, analyze and trap data, and diagnose problems common to data communication systems. Traffic from data terminal equipment DTE through data communications equipment DCE can be examined to help isolate problems, identify bit patterns, and ensure that the proper cabling has been installed.

Network monitors continuously track packets crossing a network, providing an accurate picture of network activity at any moment, or a historical record of network activity over a period of time.

They do not decode the contents of frames. Monitors are useful for baselining, in which the activity on a network is sampled over a period of time to establish a normal performance profile, or baseline.

Monitors collect information such as packet sizes, the number of packets, error packets, overall usage of a connection, the number of hosts and their MAC addresses, and details about communications between hosts and other devices.

This data can be used to create profiles of LAN traffic as well as to assist in locating traffic overloads, planning for network expansion, detecting intruders, establishing baseline performance, and distributing traffic more efficiently.

Systems administrators access the Network Performance Monitoring console through any browser in order to see live statistics on current traffic flows on the network. Given that the service is based in the cloud, it can easily monitor remote networks, just as long as that network has the agent module installed on it.

It also stores that information for analysis. Administrators can trace the journey of a packet, view conversations between endpoints, segment traffic statistics per application or per origin or source, and identify the major bandwidth hogs on the network. The service can unify both onsite, cloud-based, and remote networks to give a complete picture of all network traffic generated by the business.

The tool includes live network maps with traffic flows shown on them and it is also possible to see overloaded links or bottlenecks. Datadog has a single plan level for its Network Performance Monitoring module. Charges are levied per host per month with a discount for paying annually in advance. The service is available for a day free trial. N-able RMM is a cloud-based remote monitoring and management software package.

As this system monitors the network, it also stores metrics for analysis. Having access to all aspects of a system, including endpoints and servers, N-able has many channels of data for diagnostics and troubleshooting.

This is a data source for a wide range of diagnostic projects. The main value of these feeds lies in security. However, they also give insights into how to improve efficiency and avoid system management mistakes. LOGICcards gathers data from 5,, endpoints on 4,, networks. Comparing the data extracted from these studies, the LOGICcard system analyzes a network and is able to point out factors and settings that are missing from that system, compared to the organization of the majority of other networks.

Another LOGICcard service is a feed of warnings to look out for, such as patches that cause problems and should be held off or new internet-based scams. A guidance aspect to this service also identifies errors to avoid in network configuration and tips on how to optimize bandwidth usage. Furthermore, the topics covered by a LOGICcard feed adapt according to your responses to past advice.

The dashboard for N-able RMM is resident on the cloud. N-able RMM is a subscription service. This is a great attraction for startups because there are no upfront costs for getting set up. There are no setup fees and there is no need to fork out for a software package Instead, the subscribing company pays a little each month. Interested potential customers can access a day free trial of N-able RMM. It can help you with troubleshooting because it can diagnose network issues right down the protocol stack and identify the root of the problem.

Port monitoring is one of the network diagnostics techniques that you can use with this tool. The PRTG system includes two port monitoring sensors.

One homes in on a specified port on a particular device, the other will check a range of port numbers. This tool only monitors TCP ports. The port range sensor has one extra feature that the single port sensor does not have. You can set it to check the port with TLS protection. Both sensors report on the response time of the port and whether it is open or closed. PRTG includes network traffic analysis tools to help you troubleshoot delivery speeds. The tool includes a range of traffic monitoring techniques including route tracing to a destination with Traceroute and a Ping sweep , which will give you the response times to each node on your network.

A packet-sniffing utility can tell you which applications and endpoints are producing excessive traffic and you can query the health of the network devices to see which are congested to the point of queuing.

Paessler built a tool that covers servers and applications as well as network statuses, port response times, and services to monitor all conditions that can cause software performance issues. That monitoring is constant, so you will be able to trace back through events to spot the source of any performance issues. Paessler delivers PRTG as a cloud service or you can install the diagnostic software on your premises.

The tool installs on Windows Server environments. You can use the system for free for up to sensors. A successful ping confirms network connectivity between the two hosts and it also gives reports on packet loss. DNS is working on the local machine. That Loss figure that you see in the last line of the ping output is the number of lost packets followed by the packet loss rate in brackets.

This makes it a helpful tool in determining where a network connectivity breakdown is occurring. Basically, tracert helps you understand if the router or network that is down between your computer and a remote host is one you control or not. Again using google.

Determining the IP settings on your computer is an essential part of network troubleshooting. The ipconfig command helps you do just that. Entering ipconfig at a command prompt will return IPv4 and IPv6 addresses, subnets, and default gateways for all network adapters on a PC. This can help determine if your computer has the right IP configuration. Additionally, ipconfig can be used to change or update selected IP settings.

Netstat allows you to display active connections on your local machine. This can be helpful when determining why users are unable to connect to a given application on a server or to determine what connections are made to remote hosts from a computer.

Entering netstat at the command prompt will display all active TCP connections. Adding parameters to the netstat command will extend or alter the functionality. There are a variety of use cases for this flexible utility and it can be run in interactive mode or by entering commands directly at the command prompt.

The output above shows us that the DNS server used on our local machine was ns2. Based on the output, we can see that the FQDN associated with 8.

Sometimes you may need to determine what email servers are available on a domain. To do that, we simply need to specify that we are looking for MX records using the —ty switch.

When a dynamic addressing method is used, the IP address of each host can potentially change often. Figure shows an example of the ifconfig utility showing the IP configuration information of a host. DNS is used by everyone using the Internet to resolve commonly known domain names i.

The nslookup utility can be used to look up the specific IP address es associated with a domain name. If this utility is unable to resolve this information, there is a DNS issue.

Along with a simple lookup, the nslookup utility is able to query specific DNS servers to determine an issue with the default DNS servers configured on a host. Figure shows an example of how the nslookup utility can be used to query the associated IP address information. This utility required to be figured out is the current state of the active network connections on a host. For example, when verifying the status of a listening port on a host or to check and see what remote hosts are connected to a local host on a specific port.

It is also possible to use the netstat utility to determine which services on a host that is associated with specific active ports. Figure below shows an example of the netstat utility being used to display the currently active ports on a Linux machine. When connecting to a variety of different types of equipment, telnet, SSH, or serial client is required; when this is required both the puTTY and SecureCRT programs are able to provide these functionalities.

One of the most important Network troubleshooting tools is an IP network calculator. These can be used to ensure a correct IP address selection and with this a correct IP address configuration. Much of the information obtained from the tool becomes simpler to calculate the longer and more experience you have in the field. A very easy test that can be used to both determine the Internet bandwidth available to a specific host and to determine the quality of an Internet connection is the use of the tools available at the speedtest.