Computer Networking Protocols | Part 1

File Transfer Protocol (FTP):

If you are doing a file transfer for this normally we use FTP which is going to be authenticating ourselves providing usernames and password credentials. FTP uses TCP port 20 and 21, "Port 21" is used to set up communication between our devices and then "Port 20" is used for data transfer. FTP is not secure.

Secure Shell (SSH):

This is the way through which we can remotely connect to terminal session, maybe we are connecting to a router or switch.

Secure File Transfer Protocol (SFTP):

It is going to use a secure shell version for file transfer.

Telnet:

It is non-secure version of SSH, it is a traditional to connect to routers and switches and get access to command line interface prompt.

Domain Name System (DNS):

It runs either on TCP or UDP port 53, it is going to allow us to resolve a domain name like cisco.com to a corresponding Ip address. 

Trivial File Transfer Protocol (TFTP):

It is not secure. It does not even require authentication like FTP does.