TCP/IP Ports that may appear in Comptia A+ 1101 Exam

Dynamic Host Configuration Protocol (DHCP). Issues IP addressing information, such as IP address, subnet mask, default gateway, and DNS server address to network devices.

Domain Name System (DNS). Translates Internet names and URLs into IP addresses.

Trivial File Transfer Protocol (TFTP). It is used mostly for booting UNIX or UNIX-like systems that do not have a local disk (this process is also known as netbooting) and for storing and retrieving configuration files for devices such as Cisco routers and switches.

File Transfer Protocol (FTP). Sends and receives files from one computer to another network device; actually requires two port numbers. One to issue commands and the other for data. Port 20 is typically, but not always, used for data. FTP sends data in cleartext and is not considered safe or secure.

Hypertext Transfer Protocol (HTTP). Provides browser-based Internet communication. Not considered secure.

HTTP over SSL/TLS (Secure Sockets Layer/ Transport Layer Security). Provides encrypted HTTP communication through an SSL/TLS session.

Internet Message Access Protocol (IMAP). Supports email retrieval. Allows synchronization from multiple devices, because the mail stays on the server. This is how you can access email from various devices. The latest version is IMAP4.

Lightweight Directory Access Protocol (LDAP). Provides records related to directory services (any type of network resource, such as users, printers, phone numbers, files, access points, etc.)

NetBIOS over TCP/IP. Supports outdated applications that rely on the NetBIOS API to use a TCP/IP-based network. Also known as NBT.

Network Time Protocol. Synchronizes time between network devices.

Post Office Protocol version 3 (POP3). Supports email retrieval and stores email on a single network device, meaning the mail server deletes the mail once the user downloads it onto their device. (Contrast with IMAP).

Remote Desktop Protocol. Connects one Windows computer to a remote Windows computer, through Remote Desktop Connection.

Secure File Transfer Protocol (SFTP). Supports file transfer using the SSH protocol suite.

Secure Shell (SSH). Supports secure connectivity to a remote device and allows secure file transfer.

Server Message Block (SMB)/ Common Internet File System (CIFS). Provides access to shared network devices, files, and printers, especially in environments with computers running various different operating systems. CIFS is a version of SMB.

Service Location Protocol (SLP). Announces and discovers services in a LAN. Can be used to find printers for example.

Simple Mail Transfer Protocol (SMTP). Sends email and is commonly used with MIME (Multipurpose Internet Mail Extensions) to include non-ASCII character sets and other rich media content within email.

Simple Network Management Protocol (SNMP). Used to monitor, communicate with, and manage network devices.

Telnet. Supports connecting to a remote network device; is not secure. Basically like SSH except not encrypted. Supports username and password authentication but the data sent is not secure.

Secure POP3, or POP3S or POP3 over SSL/TLS. Used to retrieve emails securely via POP3, which facilitates encrypted communication to prevent eavesdropping. Port 110 is used for unsecure POP3 connections.