Common network protocols & associated ports you must know!
DHCP (Dynamic Host Configuration Protocol)
As we know that every device on a network must have its unique identifier which is known as IP Address (in the computer world) in order to communicate with other devices on the network. Needless to say, two computers on the same network with the same IP address will cause IP conflict and cause problems in network communication. IP addresses used to be assigned manually to a computer in older days and in the modern world this function is managed by a DHCP protocol. This dynamic IP address is issued on lease to every device and must be set at regular intervals.
DHCP protocol on a TCP/IP network provides enables automatically configuring IP Addresses, subnet masks, and other IP settings for a device connected to the network.
DHCP protocol commonly uses UDP 67/UDP 68 ports to communicate between the device and the DHCP server on a network.
DNS (Domain Name System)
DNS is a service that is built in your home router (or SOHO router) which converts the domain names to IP addresses. Computers do not understand domain names such as www.beexam.com and can only understand its IP address such as 166.62.10.4. Hence when you type this domain name (www.beexam.com) in your computer’s internet browser DNS service available in your home router automatically converts it into an IP address that other computers on the internet would understand. DNS service commonly uses UDP 389 port for communication.
LDAP (Lightweight Directory Access Protocol)
LDAP is a common protocol used on the public internet as well as on a corporate intranet for authentication and management of directories over a TCP/IP network. LDAP is recognized as a lightweight version of “Directory Access Protocol” which means it is lighter on computer code and also is a part of the standard for directory services popularly known as X.500. LDAP commonly uses TCP 389/UDP 389 ports for communication. LDAP is commonly seen being used by Windows Active Directory, Apple Open Directory, and Novelle Directory operating systems.
SNMP (Simple Network Management Protocol)
SNMP stands for “Simple Network Management Protocol” which is a central network management protocol for all network devices such as switches, routers, servers, firewalls, etc. SNMP allows network engineers and administrators to gather statistics and make configuration changes to all these remote devices on a network. SNMP commonly uses UDP 161 port for communication.
SMB (Server Message Block)
Server Message Block is a common protocol used by Microsoft Windows for print sharing and file sharing. SMB is also popularly known as CIFS (Common Internet File System). Though SMB was developed for Microsoft Windows-based computers it can also be used by Linux/Mac OS-based computers using a special software implementation known as Samba. This is useful in a scenario when in a Windows computer network a user wants to use Mac /Linux-based computer system.
SSH (Secured Shell or Secured Socket Shell)
SSH protocol is a protocol that can be used on an unsecured network to securely operate services on the network. SSH commonly uses TCP port 22. Remote command-line login and command execution performed by network administrators is facilitated by SSH.
AFP (Apple Filing Protocol)
Just like Microsoft developed SMB Apple developed its own protocol for file sharing between Mac devices which is known widely as Apple Filing Protocol. AFP commonly uses TCP 548 port for communication. AFP is stacked with features to copy, move or delete files to the file system and is used with SLP (Service Location Protocol)
