Common Ports and Their Associated Protocols in Networking

Port Number Associated Protocol (or Keyword) TCP/UDP Usage Secure Version and Port Usage
21 FTP TCP FTPS, port 989/990 Transfers files from host to host.
22 SSH TCP or UDP Secure Shell: Remotely administers network devices and systems. Also used by Secure Copy (SCP) and Secure FTP (SFTP).
23 Telnet TCP or UDP Remotely administers network devices (deprecated).
25 SMTP TCP SMTP with SSL/TLS, port 465 or 587 Sends e-mail.
49 TACACS+ TCP Remote authentication.
Can also use UDP, but TCP is the default. Compare with RADIUS.
53 DNS TCP or UDP DNSSEC Resolves hostnames to IP addresses and vice versa.
69 TFTP UDP Basic version of FTP.
80 HTTP TCP HTTPS (uses SSL/TLS), port 443 Transmits web page data.
88 Kerberos TCP or UDP Network authentication, uses tickets.
110 POP3 TCP POP3 with SSL/TLS, port 995 Receives e-mail.
119 NNTP TCP Transports Usenet articles.
135 RPC/epmap/ dcom-scm TCP or UDP Used to locate DCOM ports. Also known as RPC (Remote Procedure Call).
137–139 NetBIOS TCP or UDP Name querying, sending data, NetBIOS connections.
143 IMAP TCP IMAP4 with SSL/TLS, port 993 Retrieval of e-mail, with advantages over POP3.
161 SNMP UDP Remotely monitor network devices.
162 SNMPTRAP TCP or UDP Traps and InformRequests are sent to the SNMP Manager on this port.
389 LDAP TCP or UDP LDAP over SSL/TLS, port 636 Maintains directories of users and other objects.
445 SMB TCP Provides shared access to files and other resources.
514 Syslog UDP Used for computer message logging, especially for router and firewall logs.
A secure version (Syslog over TLS) uses TCP as the transport mechanism and port 6514.
860 iSCSI TCP IP-based protocol used for linking data storage facilities.
Also uses port 3260 for the iSCSI target.
1433 Ms-sql-s TCP Opens queries to Microsoft SQL server.
1701 L2TP UDP VPN protocol with no inherent security. Often used with IPsec.
1723 PPTP TCP or UDP VPN protocol with built-in security.
1812/1813 RADIUS UDP An AAA protocol used for authentication (port 1812), authorization, and accounting (port 1813) of users.
Also, ports 1645 and 1646.
3225 FCIP TCP or UDP Encapsulates Fibre Channel frames within TCP/IP packets.
Contrast with Fibre Channel over Ethernet (FCoE), which relies on the data link layer and doesn’t rely on TCP/IP directly.
3389 RDP TCP or UDP Remotely views and controls other Windows systems.
3868 Diameter TCP (or SCTP) An AAA protocol; can replace the RADIUS protocol.