Ports and Commands

File Transfer Protocol (FTP)

Port 20/21

Secure File Transfer Protocol (SFTP)

Port 22

Secure Shell (SSH)

Port 22

Telnet

Port 23

Simple Mail Transfer Protocol (SMTP)

Port 25

Domain Name System (DNS)

Port 53

Dynamic Host Configuration Protocol (DHCP)

Port 67/68

Trivial File Transfer Protocol (TFTP)

Port 69

Hypertext Transfer Protocol (HTTP)

Port 80

Network Time Protocol (NTP)

Port 123

Simple Network Management Protocol (SNMP)

Port 161/162

Lightweight Directory Access Protocol (LDAP)

Port 389

Hypertext Transfer Protocol Secure (HTTPS)

Port 443

Server Message Block (SMB)

Port 445

Syslog

Port 514

Simple Mail Transfer Protocol Secure (SMTPS)

Port 587

Lightweight Directory Access Protocol over SSL (LDAPS)

Port 636

Structured Query Language (SQL) Server

Port 1433

Remote Desktop Protocol (RDP)

Port 3389

Session Initiation Protocol (SIP)

Port 5060/5061

ping (Windows/Linux)

A network utility that tests connectivity between devices by sending ICMP echo requests and measuring response time and packet loss, helping to diagnose reachability and network latency

traceroute/tracert (Windows)

A network diagnostic tool that maps the path packets take from a source to a destination, showing each hop along the route and the time taken, useful for identifying routing issues or network delays

nslookup (Windows)

A command-line tool used to query Domain Name System (DNS) servers to obtain IP addresses, domain names, and DNS record information, helping troubleshoot name resolution and DNS issues

tcpdump (Linux)

A command-line network packet analyzer for capturing and inspecting network traffic in real-time, allowing administrators to diagnose network issues, monitor protocols, and troubleshoot connectivity problems

Dig (Linux)

A command-line tool used to query DNS servers for information about domain names, IP addresses, and DNS records, helping to troubleshoot DNS resolution and verify DNS configurations

netstat

A command-line tool that displays active network connections, listening ports, routing tables, and network statistics, useful for monitoring network activity and diagnosing connectivity or performance issues

ip/ifconfig/ipconfig

Displays IP configuration details such as IP address, subnet mask, and default gateway for network interfaces

Shows network interface settings and status, including IP address, MAC address, and link status

A more powerful replacement for ifconfig, used to view and configure network interfaces, routes, and addresses

arp

A protocol and command-line tool used to map IP addresses to their corresponding MAC addresses on a local network, helping devices locate each other and communicate within the same subnet

nmap

A network scanning tool used to discover devices, identify open ports, and detect services on a network, helping with security auditing, network inventory, and vulnerability assessment

show mac-address-table

A network switch command (commonly on Cisco devices) used to display the MAC address table, showing which MAC addresses are associated with specific switch ports, helping with troubleshooting, device identification, and verifying network connectivity

show route

A network device command used to display the routing table, showing known networks, associated next hops, and routing paths, helping administrators verify routes and troubleshoot connectivity issues

show interface

A network device command used to display the status and statistics of interfaces, including link status, errors, traffic, speed, duplex, and protocol information, helping to diagnose connectivity and performance issues

show config

A network device command used to display the current active configuration of a device, including interfaces, routing, VLANs, ACLs, and other settings, helping administrators verify configurations and troubleshoot issues

show arp

A network device command used to display the Address Resolution Protocol (ARP) table, showing IP-to-MAC address mappings for devices on the local network, useful for troubleshooting connectivity and identifying devices

show vlan

A network device command used to display VLAN information, including VLAN IDs, names, status, and associated ports, helping administrators verify VLAN configurations and troubleshoot network segmentation issues

show power

A network device command used to display the status of Power over Ethernet (PoE) on ports, including power availability, usage, and any faults, helping troubleshoot PoE-related issues and device power problems