Port scanner 101: An introduction to network ports and port scanningPort scanning is an integral part of every network admin's list of day-to-day network tasks. It offers insights into how your network is being connected, accessed, and used. It helps you understand your network infrastructure and enhance your network security. From mapping connected devices to listing services running in a host, port scanners help you better manage your network infrastructure. Show
In this page, we will be looking into the basics of port scanning, covering the following topics.
Types of ports in your networkA port can be an interface or physical connection that enables communication between different entities in your network. There are different types of ports which enable connectivity. For example, you can connect your external mouse or speakers through a USB port. Your external camera can be connected through your HDMI ports. While most of these ports do not require stringent monitoring in general, the switch ports and computer ports require continuous port scanning to prevent network issues. What are switch ports?The docking points in network switches are called switch ports. These ports facilitate network communication by allowing data cables from different network components to be connected to it. Once the data cables are connected, the switch enables communication by forwarding the data packets using the packet switching technique. The forwarded data packets then transmit the messages from one network entity to another. These network entities can be devices, in which case the communication happens between network devices i.e., within the network. Or, one of the connected cables() could be an internet data cable connecting the devices to the outer network. In both cases, it is important to deploy a port scanner to monitor the ports to map them to their connected devices, identify the type of port connection, and track crucial metrics such as its availability and utilization. Types of switch port connectionsBased on the type of connections switch ports enable, they are classified as:
The connection types can be illustrated in a sample network as shown below. What are computer ports?Also called host side ports, these ports enable the flow of information between different applications, services, or the internet and the computers in your network. Unlike in switch ports, data is transferred without a physical point of attachment or hardware, such as data cables. The communication is carried out based on port numbers and port services.
What is a port scanner?A port scanner tool can scan network ports to identify their connectivity details, and display the results to the user in real time. This tool plays an important role in improving network security as it provides complete visibility and control over network ports. Since ports play a crucial part in enabling network communication, the visibility offered by network port scanners help you identify unauthorized port access, malicious services running in them, and block suspicious ports. Port scanners also play an important role in analyzing network resource usage. It scans your network ports and displays the number of available ports, used ports, and device details for accessing a port such as its IP and MAC addresses. This helps you better track resource usage and enhance capacity planning. How does a port scanner work?Based on the network architecture and network requirements, port scanners use different protocols to scan. For switch portsTraditionally, network admins relied on broadcast pings from first hop routers, routers' arp entries, and native commands to check all the devices in their network responding to a ping, and use the list of MAC addresses to determine which switch port each device is connected to. This tedious process requires dedicated time and effort, and is more impractical as the network scales. Switch port mappers help easily avoid this hassle. Once you specify the switches to be monitored, the switch port mapper continually queries the switch using network protocols such as SNMP and displays the scan results. Computer ports or host side portsThese ports can be scanned using different scanning techniques such as Ping, FTP bounce, proxy, idle, ACK, SYN, or FIN scanning techniques. In general, on specifying the address range, a port scanner sends a network packet sequentially to each port within the specified address range. Based on the response received from the ports, it determines their status. Let's have a look into two of the commonly used scanning techniques,
What do you get from a port scan?Once a port scanner has scanned your network ports, it displays the following details: Switch port scansOn scanning switch ports, you can view insights such as:
Computer ports or host side port scansScanning computer ports with a port scanner displays details such as:
These results help you better understand your network ports. However, computer ports can be easily exploited, increasing your network's risk vector since these port scan results can also be obtained by external attackers scanning your network. This makes it important that you deploy an effective switch port mapping and port scanning solution in your network to stay ahead of issues and threats. Take control of your network ports with OpUtilsLooking for a reliable port scanner for your network? Try ManageEngine OpUtils, an enterprise-grade solution that offers network resource monitoring capabilities along with port scanning. The Switch Port Mapper module gives you complete control over your network switches. Providing centralized visibility, it enables simpler management with the Port View option that graphically displays the switch port connections. Enhance capacity planning and stay ahead of network issues with granular reports and instantaeous alerts. Download a free, 30-day trial or schedule a personalized live demo with our product experts to explore all the effective features OpUtils provides. Which tool can perform real time traffic and port analysis and can also detect port scan fingerprinting and buffer overflow attacks?Snort is an open source intrusion protection system (IPS) that is capable of performing real-time traffic and port analysis, packet logging, content searching and matching, as well as detecting probes, attacks, port scans, fingerprinting, and buffer overflow attacks.
Which tool can identify malicious traffic by comparing?Which tool can identify malicious traffic by comparing packet contents to known attack signatures? Explanation: An IDS, or intrusion detection system, is a device that can scan packets and compare them to a set of rules or attack signatures.
What name is given to a device that controls or filters traffic going in or out of the network?A firewall is a type of cybersecurity tool used to filter traffic on a network.
What protocol is used to collect information about traffic traversing a network?NetFlow is a protocol used to collect metadata on IP traffic flows traversing a network device. Developed by Cisco Systems, NetFlow is used to record metadata about IP traffic flows traversing a network device such as a router, switch, or host.
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