Applications

Question 1

Application layer protocols define?

Answer 1

Types of messages
Message syntax and semantics
Rules for when and how processes send and respond to messages

Question 2

What do we need to consider when coming up with new application (determining protocol)

Answer 2

Data loss (some apps can tolerate some loss), timing, throughput, security

Question 3

DNS

Answer 3

Domain name system.

Technology behind mapping host.domain.com to IP address

Question 4

Domain name space

Answer 4

DNS uses tree structured name space to identify resources on internet

Question 5

DNS database

Answer 5

Each node/leaf in name space tree names set of information contained in resource record (RR). These are organised into distributed databse

Question 6

Name servers

Answer 6

Server programs that hold info about portion of domain name tree structure and associated RRs

Question 7

Resolvers

Answer 7

Programs that extract info from name severs in response to client requests

Question 8

Explain dig command’s 5 tuple

Answer 8

domain name, time to live, internet, class of activity and values

Question 9

What are the 3 name servers we need to know about?

Answer 9

Top level domain DNS servers
Authoritative DNS servers
Local DNS server