Applications Flashcards
Application layer protocols define?
Types of messages
Message syntax and semantics
Rules for when and how processes send and respond to messages
What do we need to consider when coming up with new application (determining protocol)
Data loss (some apps can tolerate some loss), timing, throughput, security
DNS
Domain name system.
Technology behind mapping host.domain.com to IP address
Domain name space
DNS uses tree structured name space to identify resources on internet
DNS database
Each node/leaf in name space tree names set of information contained in resource record (RR). These are organised into distributed databse
Name servers
Server programs that hold info about portion of domain name tree structure and associated RRs
Resolvers
Programs that extract info from name severs in response to client requests
Explain dig command’s 5 tuple
domain name, time to live, internet, class of activity and values
What are the 3 name servers we need to know about?
Top level domain DNS servers
Authoritative DNS servers
Local DNS server