Ports and Protocols (2.1) Flashcards
TCP
Transfer Control Protocol, connection-oriented, OSI Layer 4
UDP
User Datagram Protocol, connectionless, OSI Layer 4
FTP
File Transfer Protocol
tcp/20 (data), tcp/21 (control/command)
Standard communication protocol used for the transfer of computer files from a server to a client on a computer network.
SSH
Secure Shell
tcp/22
Cryptographic network protocol for operating network services securely over an unsecured network. It’s most notable applications are remote login and command-line execution.
Telnet
Short for “teletype network”
tcp/23
Client/server application protocol that provides access to virtual terminals of remote systems on local area networks (LANs) or the Internet.
SMTP
Simple Mail Transfer Protocol
tcp/25 (plain-text), tcp/587 (encrypted)
Internet standard communication protocol for electronic mail transmission. Mail servers and other message transfer agents (MTAs) use SMTP to send and receive mail messages.
DNS
Domain Name System
udp/53
Hierarchical and distributed naming system for computers, services, and other resources in the Internet or other Internet Protocol (IP) networks.
Turns “www.google.com” into “142.250.72.174”
DHCP
Dynamic Host Configuration Protocol
udp/67 (server), udp/68 (client)
Network management protocol used on Internet Protocol (IP) networks for automatically assigning IP addresses and other communication parameters to devices connected to the network using a client-server architecture.
HTTP
Hypertext Transfer Protocol
tcp/80
Application-layer (OSI Layer 7) protocol for transmitting hypermedia documents, such as HTML. Designed for communication between web browsers and web servers.
POP3
Post Office Protocol v3
tcp/110
Application-layer (OSI Layer 7) protocol used by e-mail clients to retrieve e-mail from a mail server. POP3 and IMAP are the most common protocols for email retrieval.
NetBIOS
Network Basic Input/Output System
NetBIOS Name Service: udp/137
NetBIOS Datagram Service: udp/138
NetBIOS Session Service: tcp/139
NetBIOS provides services related to the session-layer (OSI layer 5) allowing applications on separate computers to communicate over a local area network (LAN). Simply put, NetBIOS is an API providing various networking services.
IMAP
Internet Mail Access Protocol
tcp/143
Protocol used by e-mail clients to retrieve e-mail messages from a mail server.
SNMP
Simple Network Management Protocol
udp/161, udp/162 (trap)
Protocol for collecting and organizing information about managed devices on IP networks and for modifying that information to change device behavior. Devices that typically support SNMP include cable modems, routers, switches, servers, workstations, printers, and more.
LDAP
Lightweight Directory Access Protocol
tcp/389
LDAP is an open, vendor-neutral, industry standard application protocol for accessing and maintaining distributed directory information services over an IP network.
HTTPS
Hypertext Transfer Protocol Secure
tcp/443
Extension of HTTP. Uses encryption for secure communication over a computer network, and is widely used on the Internet. Encrypted using Transport Layer Security (TLS) or, formerly, Secure Socket Layer (SSL).
