Network Port Reference

FTP Data Transfer -- data channel for file transfers

FTP Control -- command channel for file transfer sessions

SSH -- encrypted remote login and command execution

Telnet -- unencrypted remote terminal access

SMTP -- sending and relaying email messages

DNS -- domain name resolution

DHCP Server -- dynamic IP address assignment (server side)

DHCP Client -- dynamic IP address assignment (client side)

TFTP -- simple file transfer without authentication

HTTP -- standard web traffic

POP3 -- retrieving email from a mail server

NNTP -- Usenet newsgroup access

NTP -- network time synchronization

MS-RPC -- Microsoft remote procedure calls

NetBIOS Name Service -- Windows name resolution

NetBIOS Datagram -- Windows connectionless messaging

NetBIOS Session -- Windows file and printer sharing

IMAP -- accessing email on a mail server

SNMP -- network device monitoring and management

SNMP Trap -- asynchronous network device alerts

BGP -- internet routing between autonomous systems

IRC -- Internet Relay Chat

LDAP -- directory services for user authentication

HTTPS -- encrypted web traffic (TLS/SSL)

SMB -- Windows file sharing and network resources

SMTPS -- encrypted email sending (implicit TLS)

Syslog -- centralized system logging

LPD -- Line Printer Daemon for network printing

RIP -- routing information exchange between routers

DHCPv6 Client -- IPv6 address assignment (client side)

DHCPv6 Server -- IPv6 address assignment (server side)

SMTP Submission -- authenticated email sending

IPP -- Internet Printing Protocol

LDAPS -- encrypted directory services (LDAP over SSL)

IMAPS -- encrypted email access (IMAP over SSL)

POP3S -- encrypted email retrieval (POP3 over SSL)