DNS Notes

While browsing, we give the URL, 'www.xyz.com' something like that.  In internet, it is always converted into IP address for any further processing.  For conversion, we use DNS protocol, Domain Name System.

• Query & Response
• UDP protocol, 53 port

DNS Query

DNS Response

Observations

• Transaction ID is same for both Query and Response
• In flags, query is 0, response is 1
• Type: Record type.  A is mapping IPv4 address and DNS name.  MX is mapping IPv4 address and Mail Exchange server.
• Class: of a Record. belongs to 'IN' Internet name space.