Computer Sciences and Information Technology
Topic:
DNS and DNS tools questions
1. Define the following and provide an example:
(a) Root DNS Server
(b) Top Level Domain Name servers
(c) Default Name Server
2. Define the following and provide an example:
(a) Authoritative Domain Name Servers – Primary and Secondary.
(b) Master Name Server
(c) Slave Name Server
3. In the context of DNS
(a) What are the Resource Records, RR.
(b) What are the DNS Resolvers and where are they located?
(c) In the context of the RR, what is the time to live, TTL?
4. The Wi-Fi routers are expected to have a DNS Relay.
What is it? What does it do?
5. Describe the meaning of the following two Resource Records:
(a) (abc.com, 123.45.67.89, A , 9hours)
(b) (xyz.net, 89.67.45.123, MX)
6. From the RFC 1035 (www.ietf.org/rfc/rfc1035.txt) describe the RR format.
7. Go to www.misk.com/tools and enter the domain name of your choice.
Review the information provided by selecting DNSLOOKUP, WHOIS, and TRACEROUTE. What have you learned?
8. Your PC has been suspiciously pinged from IP address 91.140.0.140. Using tools that are freely available in the Web, learn as much as possible about that IP address (Domain name, physical location, owner, address, etc.)
1. Define the following and provide an example:
(a) Root DNS Server
Root DNS servers are the authoritative names of the servers that serve the root servers which are also called the DNS root zone. Example is a.root-servers.net as the host name and 198.41.0.4.2003.465.ba4ee:: 2:40 Apple, Inc.
(b) Top Level Domain Name servers
The Top Domain Name Servers is defined as the highest levels among the domain names which are located in the DNS root zone. Examples are com, org, net, gov, edu among others.
(c) Default Name Server
The Default Name Sever is used to automatically set new domain registrations to the name server which is chosen. An example is ns1.domain.com.
2. Define the following and provide an example:
(a) Authoritative Domain Name Servers – Primary and Secondary.
Authoritative domain server provides answers to the queries that are raised by DNS which includes the website IP address, mail server among others. It houses the primary name server which keeps records of the original copies of zone records and the secondary name server which is dependent on the primary server. Examples are AAAA, SOA, MX, and PTR among others.
(b) Master Name Server
Master Name Server stores the original copies for all the zone records. The changes are only made on the records stored in the master zone records. Exampls are SOA, MX among others
(c) Slave Name Server
Supports the master server and may replace it when it is not functioning well. It reduces the DNS server load from the primary name server. Example is sec.example.com
3. In the context of DNS
(a) What are the Resource Records, RR.
RRs are the foundation of building the host-name and IP addresses. In additions, all the issues that concern the DNS are resolved by RR. They exist in different formats and data.
(b) What are the DNS Resolvers and where are they located?
DNS resolvers are used to convert the Web links to IP address and therefore provide linkage between the computer and DNS infrastructure. They are located in the Internet Service Providers.
(c) In the context of the RR, what is the time to live, TTL?
TTL is the period of time in seconds that the resolver catches any record. Zero seconds is an indication that no record should be cached.
4. The Wi-Fi routers are expected to have a DNS Relay.
What is it? What does it do?
DNS relays is a situation whereby a number of machines send the DNS queries to the relay. It is used to send and receive the answers to the machines and store queries for a short time.
5. Describe the meaning of the following two Resource Records:
(a) (abc.com, 123.45.67.89, A , 9hours)
Hosts address (A) resource record and Maps domain name (abc.com) to an internet IP address 123.45.67.89 for 9 hours.
(b) (xyz.net, 89.67.45.123, MX)
Host Master Name server and maps the domain name xyz.net to an internet of IP address 123.45.67.89.
6. From the RFC 1035 (www.ietf.org/rfc/rfc1035.txt) describe the RR format.
The format is used to describe the registration by organisations to administer the high level domains and delegate to the subzones. It, therefore, contains the authoritative name server if it is not known, maps and returns it to the local name server.
7. Go to www.misk.com/tools and enter the domain name of your choice.
Review the information provided by selecting DNSLOOKUP, WHOIS, and TRACEROUTE. What have you learned?
The tool provides means to view specific DNS, the ownership and the path where it is located.
8. Your PC has been suspiciously pinged from IP address 91.140.0.140. Using tools that are freely available in the Web, learn as much as possible about that IP address (Domain name, physical location, owner, address, etc.)
The owner of the address is Wind Hellas Telecommunications located in Athens Greece and hostname is adsl-140.91.140.0.tellas.gr and domain name www.windhellastelecommunications.com.
