Protocol Services & Related Port no

Port No	Protocol Service
1	ICMP – Internet Control Message Protocol (Ping Service)
2	IGMP - Internet Group Management Protocol
6	TCP – Transmission Control Protocol
8	EGP - Exterior Gateway Protocol
17	UDP – User Datagram Protocol
20, 21	FTP- File Transfer Protocol (20 port used in case of Unix Server)
22	SSH – Secure Shell (Putty)
23	Telnet (Access any device Remotely)
25	SMTP – Simple Mail Transfer Protocol
53	DNS – Domain Name Service
67,68	DHCP – Dynamic Host Configuration Protocol(Client & Server)
69	TFTP – Trivial File Transfer Protocol (use to upload IOS)
80	HTTP – Hyper Text Transfer  Protocol (Use for web Services)
110	POP 3(Post office Protocol) Used receiving mails
123	NTP – Network Time Protocol
443	HTTPS
3389	RDP – Remote Desktop Protocol