Jun 08, 2019

Small briefing of protocols | Part-1

Image: Small briefing of protocols | Part-1

Protocols are the set of rules that devices are agreed upon before the data transmission. This first part of the series which give answer to the questions what are those protocols, when did they first came, which ports do they use etc. 

[Note: To know about the protocols in details click on the RFC <NUMBER> links]

HTTP(Hyper Text Transfer Protocol)

Used for browser requesting resources from a server. Available versions are: 1.0 (RFC 1945), 2.0 (RFC7540). Methods available are: GET, HEAD, POST, PUT, DELETE, CONNECT,OPTIONS, TRACE, PATCH etc. Port used: 80 and 443 (secure). This is a TCP protocol.

SMTP(Simple Mail Transfer Protocol)

Used for Delivering mailsto servers. Available in (RFC 821). Available methods are: HELO, MAIL,RCPT, SEND, DATA, VRFY, AUTH, RSET, QUIT etc. Port used: 25. This is a TCP protocol.

FTP(File Transfer Protocol)

Used for downloading or uploadingfile from or to server. Available in (RFC 959). Available methods are thecommon file handling commands of UNIX system. Port used: 20/21. This is a TCP protocol.POP(Post Office Protocol) Client connect, retrieve, store them andfinally delete them from server. Available in POP (RFC 918), POP3 (RFC1081). Available methods are: USER, PASS, QUIT, STAT, RETR, DELE,RSET etc. Port used: 110 and 995 (secure).

IMAP(Internet Message Access Protocol)

Used for complete managementof mailbox. User can download a message using different clients and keepa copy on the server until explicitly deleted.  Available in (RFC 3501). Available methods are: APPEND, CHECK, SEARCH, SELECT, STORE etc. Port used: 143 and 993 (secure).

TELNET(TELetype NETwork)

Provides a bidirectional interactivetext-oriented communication facility.  Available in (RFC 15).  Availablemethods are: CLOSE, DISPLAY, OPEN, SET, SEND, STATUS, UNSET,QUIT etc. Port used: 23. This is a TCP protocol.

Other useful Ports are:

SNMP (Simple Network Management Protocol) Management and Monitoring of networks, Application layer protocol, Uses ports UDP 161 and 162.

IGMP(Internet Group Multi-casting Protocol) Uses IPv4, manageby IP Encapsulation.

ICMP(Internet  Control  Message  Protocol) Uses  IPv6,  manage  by Multi-cast Listener Discovery.

ARP(Address Resolution Protocol) Find out MAC address from IPv4,works on Layer 2 to 3, replaced by NDP in IPv6.

RARP(Reverse Address Resolution Protocol) Find out IP addressfrom MAC, works on Layer 3 to 2, replaced by BOOTP7 then DHCP in IPv6.



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