Linux Discussion

Linux Discussion
DNS Resolution and TCP/IP Troubleshooting
Discuss how you would configure your Linux distribution to perform name resolution using DNS.
To configure Linux distribution to perform name resolution using DNS requires one top surf the web, type the address bar to be directed to the webpage. However, Linux would not function with alphanumeric domain names since the alphanumeric domain name has to be resolved into a binary IP address (Ganapathy, 2014). Therefore, to configure Linux distribution to perform name resolution on DNS, it is important to ensure the IP settings on a Linux network are specified based on the system hostname and the IP address of the DNS server that will be utilized for name resolution. Computer and network services utilize the IP address and the DNS to route users’ requests to the site requested for access. The DNS acts like an internet phonebook, which holds the IP address connected to the domain server.
Compare and contrast the following programs which are helpful in debugging TCP/IP networks: nslookup, host, dig, whois.
DNS and TCP/IP network issues require diagnosing and troubleshooting with the help of several tools availed by Linux. The tools include nslookup command that offers capabilities of non-interactive and interactive of servers by UP address or domain name. The interactive mode enables the information on host and domains to be viewed, while the non-interactive mode enables the printing of the host and information that is requested from servers (Ubuntu, 2019). The host tool is used as a command to find the IP address of a domain. Another tool is a dig, which is mainly used during an extensive issue with the IP address or name has the capabilities of providing depth debugging configuration for requested resolution. Lastly, whois is another IP address resolution utility. Whois obtain information of the requested IP address or domain through the database.
Secure or Insecure Shell
Discuss the purpose of SSH and the advantages and disadvantages of using SSH on your Linux distribution. How do you configure SSH? From a cybersecurity perspective, what is the best way to control SSH access?
Secure SHell (SSH) is a device that provides security used to access another computer from a remote location allowing two computers in an insecure medium such as the internet to securely exchange information. Running SSH involves two major components, the OpenSSH-server and the OpenSSH-client. A secured connection enables the server component to communicate with the client component.
The advantages of SSH include its ability to secure remote access, securing network infrastructure components from attacks, and easily conducting automated and secured file transfer between networks or systems in the unsecured medium. SSH also helps the user to avoid been seen by random scans and make it difficult for attackers o locate the user server (Rouse, 2018). Another advantage of SSH is that the user is less exposed to hackers due to bugs in sshd or week private keys. The disadvantages of SSH include firewall rules associated with the SHH services that will always need to be inspected or modified during any change made making running SSH expensive and sometimes time-consuming. Another issue regarding SSH is that when using outsourced server monitoring the third party should be constantly be made aware of any port change top avoid potential threats that may cause server downtime.
To control SSH access involves permitting or denying SHH connections from particular machines, internet domains, or users. The control of SSH access can be conducted through authentication such as password authentication that accepts or rejects login identification (O’Reilly, 2019). The use of public-key authentication enables the verification of the identity of the user through cryptographic keys. Another access control authentication that can be applied is the rhosts authentication which verifies an SSH client’s identity by checking the remote username and hostname.

References
Ganapathy, L. (2014, January 6). How to Install and Configure DNS Server in Linux. The Geek Stuff. Retrieved from https://www.thegeekstuff.com/2014/01/install-dns-server/
Rouse, M. (2018). Secure Shell (SSH). TechTarget. Retrieved from https://searchsecurity.techtarget.com/definition/Secure-Shell
O’Reilly. (2019). Letting People in: Authentication and Access Control. Retrieved from https://docstore.mik.ua/orelly/networking_2ndEd/ssh/ch05_05.htm
Ubuntu. (2019). nslookup – Query Internet Name Servers Interactively. Retrieved from http://manpages.ubuntu.com/manpages/cosmic/man1/nslookup.1.html