The most common application layer protocols include DHCP used to obtain client IP addresses and configuration information, DNS for hostname resolution, HTTP, SMB, POP/SMTP, and FTP for the most common network services and SIP, RTP, and RTCP for VoIP and video conferencing.

Extensive coverage of all the upper layer protocols is beyond the scope of this book. A brief overview of DHCP and DNS will be provided, as these protocols universally support network operations and HTTP as an example of one of the most common application layer protocols. The reader is encouraged to research any or all of these protocols further depending on their scope of interest and need to meet the analysis tasks being addressed.