DNS is used to translate word-based addresses of systems (such as http://www.whatsnew.ng ) to the corresponding numerical IP i.e After typing a web address,the computer needs to understand what numerical IP addresses it needs to contact, and this is accomplished through DNS servers.
Q1. Does DNS work for email server ?
Yes,it works for Web Site, Mail Servers, and anything else based on the domain name.
Q2. How ?
Any request for anything related to the domain name gets sent to one of the default servers i.e ( NS1.whatsnew.ng , NS2.whatsnew.ng ) In response, the DNS server sends back the IP address that you should contact.
Q3. What does NS1 and NS2 means and how does it comes into DNS task ?
Normally, all domains have at least two DNS servers as seen through WHOIS lookups such as NS1.whatsnew.ng and NS2.whatsnew.ng, and any request for anything related to the domain name gets sent to one of these servers. In response, the DNS server sends back the IP address that you should contact.
q4. What terms will you use to describe of mapping of hostnames to IP addresses.
Answer : Forward DNS
Q5. What does Reverse DNS means ?
The mapping of IP addresses to hostnames.
Q6. Explain the following words one after the other
http://www.whatsnew.ng , whatsnew.ng, 10.199.212.8.2.names.whatsnew
www means worldwideweb
.ng is a Top Level Domain (TLD) under the root zone.
whatsnew.ng is is a zone under the ng. TLD.
10.199.212.8.2.dns.whatsnew is a zone referencing all IP addresses which fall under the 0.199.212.8.2.* IP address space.
TLD is how DNS is coordinated across the Internet through a somewhat complex system of authoritative root.
RootZone : An individual domain, subdomain, or portion of the DNS administered by the same authority
Q6A. In one line, explain DNS
DNS are used for mapping URLs to an IPs
Q7. Explain how DNS really works. Be concise and straight to the point.
Suppose you type URL whatsnew.ng into your browser. The browser contacts a DNS server to get the IP address. A DNS server search for an IP address by contacting one of the root DNS servers. The root servers know the IP addresses for all of the DNS servers that handle the top-level domains (.COM, .NET, .NG, etc.). Your DNS server would ask the root for whatsnew.ng, and the root would say, “I don’t know the IP address for whatsnew.ng, but here’s the IP address for the .ng DNS server.”
Your name server then sends a query to the .ng DNS server asking it if it knows the IP address for whatsnew.ng . The DNS server for the NG domain knows the IP addresses for the name servers handling the whatsnew.ng domain.