Question

Discuss how you would configure your Linux distribution to perform name resolution using DNS. Compare and contrast the following programs which are helpful in debugging TCP/IP networks: nslookup, host, dig, whois. Ensure you provide terminal output in your discussion.

Answer 1

Compare and contrast the following programs which are helpful in debugging TCP/IP networks: When diagnosing and troubleshooting DNS and TCP/IP network issues, it’s important to know and understand the tools available to assist in finding the root cause of the problem. Luckily, Linux innately provides a few utilities to delve deeper into finding the underlying causes using the nslookup, host, whois, and dig commands.1) nslookup – The nslookup command allows for non-interactive or interactive lookup capabilities of local and internet servers by IP address or domain name ("Ubuntu Manpage: nslookup - query Internet name servers interactively", 2017). The command is able to view information of hosts and domains in interactive mode ("Ubuntu Manpage: nslookup - query Internet name servers interactively", 2017). In non-interactive mode is able to print the name of a host along with the requested information ("Ubuntu Manpage: nslookup - query Internet name servers interactively", 2017).2) host – The host command is a simple name resolution utility used to find the IP address of a domain (TestOut Linux Pro, 2017).

3) dig – If there are extensive issues with name or IP address resolution, then using the dig command will most likely be your best tool in resolving the issue. The dig tool is able to provide in-depth debugging configuration information for name resolution requests by using the domain or IP address ("11.2.4. Using the dig Utility", 2017). Additionally, dig can isolate name resolution to specific records including A, AAAA, PTR, CNAME, P, IN, MX, SOA, and TXT records ("11.2.4. Using the dig Utility", 2017).4) whois – Another name and IP address resolution utility which queries a whois database to obtain information about the requested domain or IP Address ("WHOIS", 2017). Information typically obtained from a whois database includes contact details for the individual or entity responsible for a domain name or IP address block range ("WHOIS", 2017).11.2.4. Using the dig Utility. (2017). Docs.fedoraproject.org. Retrieved 17 February 2017, from TestOut Linux Pro (Version 4.2.0). (2017). Pleasant, Utah.Ubuntu Manpage: nslookup - query Internet name servers interactively. (2017). Manpages.ubuntu.com. Retrieved 17 February 2017, from WHOIS. (2017). Software.opensuse.org. Retrieved 17 February 2017, from Derrick A. - Local Security Good PracticesContains unread post sections for Derrick A. - Local Security Good PracticesDerrick Agyiri posted Feb 17, 2017, 11:19 AM SubscribeIn my opinion the most important security practice to help harden my Linux distribution is user training and awareness. The administrator should be trained never to log in as the root user (IBM 2014). Instead, he/she should use sudo to perform root-level tasks when required/needed. This improves system security without compromising the root account password.

The host domain utility is one of the most useful tools to perform DNS lookups. Popular uses of host command include resolving IP addresses, reverse IP and domain name records, test ISP DNS servers, but it can also be used to check for different types of DNS records, such as MX and NS.