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Port & Protocol Reference

52 essential ports for Security+, Network+, and CCNA exams. Study the table or test yourself in quiz mode.

Showing 52 of 52 ports
PortProtocolServiceDescriptionExams
20TCPFTP DataFile Transfer Protocol – data channel
Network+CCNA
21TCPFTP ControlFile Transfer Protocol – control channel
Network+CCNASecurity+
22TCPSSHSecure Shell – encrypted remote access
Security+Network+CCNA
23TCPTelnetUnencrypted remote terminal access
Network+CCNA
25TCPSMTPSimple Mail Transfer Protocol – outbound email
Security+Network+
49TCP/UDPTACACSTerminal Access Controller Access Control
Security+CCNA
53TCP/UDPDNSDomain Name System – name resolution
Network+CCNASecurity+
67UDPDHCP ServerDynamic Host Config – server to client
Network+CCNA
68UDPDHCP ClientDynamic Host Config – client to server
Network+CCNA
69UDPTFTPTrivial FTP – simple no-auth file transfer
Network+CCNA
80TCPHTTPHypertext Transfer Protocol – web traffic
Network+Security+CCNA
88TCP/UDPKerberosAuthentication protocol
Security+
110TCPPOP3Post Office Protocol v3 – email retrieval
Security+Network+
119TCPNNTPNetwork News Transfer Protocol
Network+
123UDPNTPNetwork Time Protocol – time sync
Network+CCNASecurity+
135TCPRPC/DCOMMS Remote Procedure Call
Security+
137UDPNetBIOS-NSNetBIOS Name Service
Network+Security+
138UDPNetBIOS-DGMNetBIOS Datagram Service
Network+Security+
139TCPNetBIOS-SSNNetBIOS Session Service
Network+Security+
143TCPIMAPInternet Message Access Protocol
Security+Network+
161UDPSNMPSimple Network Management Protocol – queries
Network+CCNASecurity+
162UDPSNMP TrapSNMP unsolicited alert messages
Network+CCNA
179TCPBGPBorder Gateway Protocol – internet routing
Network+CCNA
194TCPIRCInternet Relay Chat
Security+
389TCPLDAPLightweight Directory Access Protocol
Security+Network+
443TCPHTTPSHTTP over TLS – secure web traffic
Network+Security+CCNA
445TCPSMBServer Message Block – Windows file sharing
Security+Network+
465TCPSMTPSSMTP over SSL – secure email sending
Security+
500UDPIKE/ISAKMPIPsec key exchange
Security+Network+
514UDPSyslogSystem logging protocol
Network+Security+
515TCPLPDLine Printer Daemon – printing
Network+
587TCPSMTP SubmissionAuthenticated email submission
Security+
636TCPLDAPSLDAP over SSL
Security+
989TCPFTPS DataFTP over TLS – data channel
Security+Network+
990TCPFTPS ControlFTP over TLS – control channel
Security+Network+
993TCPIMAPSIMAP over SSL
Security+Network+
995TCPPOP3SPOP3 over SSL
Security+Network+
1080TCPSOCKSSOCKS proxy protocol
Security+
1194UDPOpenVPNOpenVPN tunnel protocol
Security+Network+
1433TCPMSSQLMicrosoft SQL Server
Security+
1521TCPOracle DBOracle Database listener
Security+
1701UDPL2TPLayer 2 Tunneling Protocol
Security+Network+
1723TCPPPTPPoint-to-Point Tunneling Protocol – VPN
Security+Network+
1812UDPRADIUS AuthRemote Authentication Dial-In User Service
Security+CCNA
1813UDPRADIUS AcctRADIUS accounting
Security+CCNA
2049TCP/UDPNFSNetwork File System
Network+
3306TCPMySQLMySQL database
Security+
3389TCPRDPRemote Desktop Protocol
Security+Network+
5060TCP/UDPSIPSession Initiation Protocol – VoIP
Network+CCNA
5900TCPVNCVirtual Network Computing – remote desktop
Security+Network+
8080TCPHTTP-AltAlternate HTTP port, often web proxies
Network+CCNA
8443TCPHTTPS-AltAlternate HTTPS port
Network+
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About the Ports & Protocols Reference

The Certsqill Ports & Protocols Reference is a fast, searchable list of the ports and protocols you need to know for the CompTIA Security+, Network+ and Cisco CCNA exams. Search by port number or service name, filter to a specific exam, and see the port, the transport protocol (TCP or UDP), and a short description of what each service does — then switch to quiz mode to lock the numbers into memory.

How to use the Ports & Protocols Reference

  1. Search. Type a port number, service name, or keyword (e.g. “443”, “SSH”, or “email”) into the search box.
  2. Filter by exam. Narrow the list to the ports you need for CompTIA Security+ or Network+.
  3. Read the detail. For each entry, see the port number, whether it runs over TCP or UDP, and a short description of the service.
  4. Quiz yourself. Switch to quiz mode to test whether you can recall the port for a given service under exam pressure.

Frequently asked questions

What port does HTTPS use?

HTTPS uses TCP port 443. Plain, unencrypted HTTP uses TCP port 80.

What port does SSH use?

SSH uses TCP port 22. It provides encrypted remote administration and file transfer (SFTP/SCP), replacing insecure protocols like Telnet on port 23.

Which ports does DNS use?

DNS uses port 53 on both UDP (standard name queries) and TCP (zone transfers and responses larger than 512 bytes).

What ports do FTP and SFTP use?

FTP uses TCP ports 21 (control) and 20 (data). SFTP is different — it runs over SSH on TCP port 22. FTPS (FTP over TLS) commonly uses port 990.

Which ports should I memorize for Security+?

Common ones include 20/21 (FTP), 22 (SSH/SFTP), 23 (Telnet), 25 (SMTP), 53 (DNS), 67/68 (DHCP), 69 (TFTP), 80 (HTTP), 110 (POP3), 143 (IMAP), 161/162 (SNMP), 389 (LDAP), 443 (HTTPS), 445 (SMB), 636 (LDAPS), 993 (IMAPS), 995 (POP3S), and 3389 (RDP).

What is the difference between TCP and UDP?

TCP is connection-oriented and reliable — it establishes a session and retransmits lost data — and is used by HTTP, SSH and email. UDP is connectionless and low-overhead, used by DNS queries, DHCP and streaming, where speed matters more than guaranteed delivery.

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