This chapter covers the following topics from the official CompTIA Network+ blueprint:
- Identify common TCP and UDP default ports
- Explain the function of common networking protocols
- Summarize DNS concepts and its components
We will analyze some of the most common Application Layer services that a network engineer will encounter on a daily basis, as well as learn the well-known default ports assigned to those application services. The objectives are to identify common TCP and UDP protocols, analyze their functionality, and learn the most common port numbers. The information presented in this chapter is very useful in various fields of computer networking and will assist in troubleshooting networks.
The most common protocols, organized by the TCP/IP layer they operate at, are presented in Table 5.1 below:
Table 5.1 – TCP/IP Layers and Their Protocols
|
TCP/IP Layer |
Protocol |
| Application | HTTP
HTTPS/TLS FTP TFTP POP3 SMTP IMAP SIP RTP DHCP DNS Telnet SSH SNMP NTP |
| Transport | TCP
UDP |
| Internet | IPv4
IPv6 ICMP IGMP |
| Network Access | ARP |
We will analyze each of these protocols, starting with application protocols and continuing with management and networking protocols.