Network Tools and Commands

CompTIA+ Network Learning

Wireless analyzers

Specialized software used to conduct wireless surveys and ensure proper coverage and prevent overlap between access point coverage zones and channels.

Protocol analyzers and packet captures

Software tools used to capture and analyze signals and data traffic over a communication channel, such as Wireshark.

Bandwidth speed test

Tools used to measure the real-world throughput of a network connection, such as Speedtest.net.

Port scanners

Software tools used to determine which ports are open on a network and reveal the presence of security devices, such as Nmap.

iPerf

Software tool used to measure the maximum achievable bandwidth on an IP-based network by creating data streams between two ends of a connection.

NetFlow analyzers

Software tools used to monitor, troubleshoot, and analyze traffic flow data to conduct capacity planning and optimize resource usage.

TFTP servers

Servers used for simple file transfers, often used by embedded devices or systems to retrieve firmware or configuration information during boot-up.

Terminal emulators

Software tools that allow a host computer to access and control another computer remotely through a command line or graphical interface, such as PuTTY.

IP scanners

Tools used to search for and detect IP addresses and other information related to devices on a network, such as Nmap or Angry IP Scanner.

IP addresses

Identifiers assigned to devices connected to a network.

Ports

Communication endpoints in a network where specific services are accessed.

Wi-Fi analyzer

Tool used to analyze and optimize Wi-Fi networks.

Packet analyzer

Tool used to capture and analyze network packets.

Packet capture tool

Tool used to capture network packets for analysis.

Bandwidth speed test tool

Tool used to measure the speed of an internet connection.

Port scanner

Tool used to scan for open ports on a network.

iPerf

Tool used to measure network performance.

NetFlow analyzers

Tools used to analyze network traffic using NetFlow data.

TFTP servers

Servers used for Trivial File Transfer Protocol.

Terminal emulators

Tools used to access and control remote systems through a terminal interface.

IP scanner

Tool used to scan IP addresses on a network.

Nmap

A widely used network scanning tool.

Wireshark

A popular packet analyzer used for network troubleshooting.

Ping

Command-line tool used to check connectivity between devices.

Traceroute

Command-line tool used to trace the path between a device and its destination.

Border Gateway Router

A router that connects a local network to the internet and acts as the gateway for all outgoing and incoming traffic.

Ping

A network utility used to test the reachability of a host on an IP network and measure the round-trip time for packets sent from the source to the destination host.

Default Gateway

The IP address of the router that a device uses to send traffic to destinations outside of its own network.

Network Card

Also known as a network interface card (NIC), it is a hardware component that allows a computer to connect to a network and communicate with other devices.

DHCP

Dynamic Host Configuration Protocol is a network protocol that automatically assigns IP addresses and other network configuration parameters to devices on a network.

APIPA

Automatic Private IP Addressing is a feature in Windows that automatically assigns a private IP address to a device when it cannot obtain an IP address from a DHCP server.

DNS

Domain Name System is a hierarchical decentralized naming system that translates domain names to IP addresses, allowing users to access websites using easy-to-remember domain names instead of numerical IP addresses.

Lease Time

The duration for which a device is assigned a specific IP address by a DHCP server before it needs to renew the lease.

Mac Address

Media Access Control address is a unique identifier assigned to network interfaces for communications on the physical network segment.

Traceroute

A network diagnostic tool used to track the path that packets take from a source device to a destination device, showing the routers or hops along the way.

Ipconfig

A command-line tool used in Windows to display and manage the TCP/IP network configuration settings of a device, including IP address, subnet mask, default gateway, and DNS server.

Ifconfig

A command-line tool used in Unix, Linux, and OS X systems to display and configure network interfaces, including IP address, subnet mask, and other network settings.

IP

A command-line tool in Unix, Linux, and OS X systems that provides a suite of commands for configuring and managing IP addresses, routing, and other network-related tasks. It is a modern replacement for ifconfig.

Promiscuous mode

A mode in which a network device listens to all the traffic on a network, not just the traffic destined for its own MAC address.

IP link set dev

A command used to configure network interfaces in Linux, such as enabling promiscuous mode on a specific device.

Packet sniffer

A tool used to capture and analyze network traffic.

Packet capture

The process of capturing and storing network packets for analysis.

IP link set eth0 down

A command used to disable a network interface named eth0.

IP link set eth0 up

A command used to enable a network interface named eth0.

IP command

A command-line tool in Linux used for network configuration and troubleshooting.

nslookup

A command-line tool used to query the Domain Name System (DNS) for mapping between domain names and IP addresses.

DNS

Stands for Domain Name System, a system that translates domain names into IP addresses.

Non-interactive mode

A mode in nslookup where only the requested information for a host or domain name is displayed.

Interactive mode

A mode in nslookup that allows more in-depth queries and control over the environment.

MX records

Mail Exchange records, which specify the mail servers responsible for accepting email messages for a domain.

CNAME records

Canonical Name records, which specify an alias for a domain name.

dig

A command-line tool used to conduct DNS queries against name servers.

A records

Address records, which map domain names to their corresponding IP addresses.

Hostname

A command-line tool used to display the hostname portion of a computer's full name.

FQDN

Stands for Fully Qualified Domain Name, which includes both the hostname and the domain name.

ARP

Stands for Address Resolution Protocol, used to display and modify entries in the ARP cache on a system.

ARP cache

A table that stores IP addresses and their associated MAC addresses.

MAC address

Stands for Media Access Control address, a unique identifier assigned to network interfaces.

route

A command-line tool used to view and modify the IP routing table on a system.

nbtstat

A command-line tool used to troubleshoot NetBIOS over TCP/IP (NBT) name resolution issues.

netstat

A command-line tool used to display network connections, routing tables, and network statistics.

ARP entry

A record in the cache of a layer three switch that maps an IP address to a MAC address.

Default ARP timeout

The default time period, 21,600 seconds (approximately six hours), after which an ARP entry will be deleted from the cache unless prevented.

Clear ARP cache

The process of deleting all the ARP entries stored in the cache of a device.

Route command

A command used to view and manipulate the IP routing table in Windows, Linux, Unix, or OS X systems.

Default route

The route that is taken when there is no other route available for a particular IP destination address.

Interface

The network interface card that receives traffic for a specific network destination.

nbtstat command

A Windows command used to view current connections and statistics for devices communicating using netBIOS over the TCP/IP protocol.

Netstat command

A command used to display information for IP-based connections on a client, including current sessions, source and destination IPs, and port numbers.

PID

Process Identification Number, used to identify the application or service that owns a network connection.

-s option

An option in the netstat command that displays statistics for IPv4, IPv6, ICMPv4, and ICMPv6 connections, as well as TCP and UDP statistics for both IPv4 and IPv6.

Telnet

A protocol used to test network connectivity and issue commands using text-based interfaces. It is an older and insecure protocol, and it is recommended to use SSH instead.

SSH

A secure protocol used for remote login and command execution on network devices. It is a more secure alternative to Telnet.

Virtual terminal connections

Connections established between a client and a server using Telnet or SSH protocols.

Console cable connection

A direct connection to a router or switch using a console cable, providing a trusted and direct connection to the device.

TCPDump

A command-line tool used to display TCP/IP and other packets being transmitted or received over a network. It can be used to capture network traffic for analysis.

PCAP file

A Packet Capture file created by TCPDump, which can be loaded into tools like Wireshark for further analysis.

Nmap

Network Mapper, a tool used to discover hosts and services on a computer network by sending packets and analyzing the responses. It can be used for port scanning, IP scanning, and service detection.

Network platforms

Refers to routers, switches, and firewalls regardless of the brand or manufacturer. These devices have their own command line interfaces for configuration, monitoring, and troubleshooting.

Show interface

A command used to display statistics for a network interface on a device. It shows if the interface is up or down, line protocol status, IP address, bandwidth, MTU size, errors, and collisions.

Show config

A command used to display the current system configuration of a device. It shows shared secrets, system settings, SNMP settings, IP settings, VMPS settings, DNS settings, and more.

Show route

A command used to display the routing table of a device. It shows the routes and gateways used for forwarding network traffic.

DNS domain

The domain name system (DNS) domain used by the network, in this case, cisco.com.

TACacs plus configuration

The configuration settings for the TACacs plus protocol, including servers, invalid attempts allowed, and timeout period.

IPX

An older network protocol used for communication, with specific configuration settings on the device to allow IPX traffic bridging.

VTP settings

VLAN Trunking Protocol (VTP) settings that enable the device to operate in server mode and exchange VLAN information with other Cisco devices.

Spanning tree protocol settings

Configuration settings for the spanning tree protocol (STP), including enabling STP and setting the max age to 20.

CGMP

Cisco Group Management Protocol (CGMP) settings that enable the protocol, used by Cisco switches for group management of IP traffic.

CIS Log

Configuration settings for the CIS Log, including enabling/disabling for console and server, and setting logging levels.

NTP section

Network Time Protocol (NTP) configuration settings, including the NTP server, time zone, and enabling/disabling NTP clients.

Permit list

An access control list (ACL) in the form of a permit list, which is currently disabled.

Module configuration

Configuration settings for the first module in the device, a two-port 100 base TX fast Ethernet device.

Show route

Command used to display the current state of the routing table on the device, specifically for IP-based networks.

Gateway of last resort

The default gateway used if traffic cannot be routed to any other listed routes.

Route derivation

Indicates how the route is derived, such as IGRP, RIP, OSPF, directly connected, static route, EGP derived, or BGP derived.

Route type

The type of route when learned through OSPF, indicated by codes like E2 for OSPF external type 2 routes.

Remote network address

The address of the remote network for the route.

Administrative distance and metric

The administrative distance and metric values for the route, indicating the believability and preference of the route.

Next router address

The IP address of the next router to reach the remote network.

Route update time

The last time the route was updated, displayed in hours, minutes, and seconds.