Network System Administration Report for 7COM1029, Spring 2020

This report details the implementation of a proposed network design utilizing Linux network services, focusing on resolving network connectivity and performance issues commonly caused by DHCP and DNS misconfigurations. The study includes the installation and configuration of essential TCP/IP suite components like DNS and DHCP servers, along with SSH securing and iptables implementation. The experimental work encompasses the setup of a DHCP server, DNS server within a virtual machine, real and virtual host configurations, client/server interactions, and quality of service implementation. The report also covers securing SSH and utilizing iptables for network security. The testing and evaluation phase assesses DNS and DHCP functionality, along with virtual host performance, concluding with a discussion of the obtained results and their implications for network system administration. The report emphasizes the importance of network security and the challenges faced by network administrators in maintaining efficient and secure network operations.

Network System Administration

Abstract
Any network can face network connectivity issues or performance based problems. The main
culprits for these issues are DHCP and DNS. Thus, this indicates that the existing system
protocols require proper configuration. The purpose of this report is to implement a proposed
network design by utilizing the Linux network services. The installation and configuration of
the required TCP/IP suite i.e., DNS and DHCP server, including SSH securing, iptables is
done. The report is concluded with the results obtained from the tests and evaluation of DNS,
DHCP and virtual hosts.
Keywords: DHCP, DNS, SSH, iptables, Network System administration

Table of Contents
1. Introduction.......................................................................................................................1
1.1 Background................................................................................................................1
2. Literature Review.............................................................................................................2
2.1 Summary....................................................................................................................3
3. Scope and Limitations of the Project..............................................................................3
4. Proposed Network Design................................................................................................3
5. Experimental Work & Analysis......................................................................................4
5.1 Installation and Configuration of DHCP Server....................................................4
5.2 DNS Server in Virtual Machine...............................................................................9
5.3 Real Host and Virtual Host Set-up........................................................................20
5.4 Client/Server Configuration and Interactions......................................................27
5.5 Quality of Service Implementation........................................................................30
5.6 Securing SSH...........................................................................................................31
5.7 iptables......................................................................................................................36
6. Testing and Evaluation...................................................................................................38
7. Conclusion.......................................................................................................................41
References...............................................................................................................................43

1. Introduction
A network comprises a collection of systems like server platforms and desktops which
are connected to share the resources. The resources can either be the storage devices, folders
or printers and so on. Network offers a centralized accessing of resources which is utilized by
all the organizations. It is essential to take care of the network operations, which is
challenging. Additionally, the network must also be secured from the hackers. The most
common problems include network, systems and resource configuration. The complexity can
be determined by the size of the network. And the advancement in the telecommunication
and its market has impact on the hardware and software market where the users are setting up
system and networking together without having complete knowledge about networking,
systems and security.
In this report, the aim is to implement a proposed network system design in the
existing system, where the Linux network services will be used. The intension is to enhance
the existing network system and provide a new network design that is better that the existing
network system. To meet the new requirements of the proposed network design, the DNS,
and DHCP (Dynamic host configuration protocol) might need installed and configured.
1.1 Background
The network based problems are mostly faced by the network administrators, end
users and the owners of businesses. With the advancing mobile technology, the corporate
networks are including new complicated layers, which complicates things more. This
demands the need of faster and highly secure technologies to face the connectivity issues and
other issues. But, while setting up the systems, the key point which leads to disruption
includes loss of main power source, wrong cabling/wireless configuration, misconfigured
protocols and misconfigured network services. On the other hand, it is highly essential to take
care of the problems related to rights, credentials and permissions; network performance; and
problems related to TCP/IP or protocols. The other problem that must be considered is client
computer access shared resources’ configuration. Thus, the target is to troubleshoot and get to
the problem’s root cause, and make necessary changes in the proposed design (J. Shimonski,
2009). The troubleshooting methods is effective approach as it has the capacity of solving the
actual problem, and it is time consuming but effective method for finding the exact issue.
However, it is difficult, but necessary as working on a network could be confusing for
troubleshooting. Moreover, the network services must be enhanced to enjoy its offered
facilities.
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2. Literature Review
As per (Younes, 2016), with the increasing growth and widening of the internet the
network security has become a major concern, and it cannot be denied. There are many
methods for providing network security in transport layer, application layer, and network
layer, but it is seen that the data link layer or the layer-2’s security isn’t addressed so far.
From this paper it is observed that the data link layer protocols utilized in LANs doesn’t have
security features. The network protocol like DHCP is mostly utilized for the configuration of
host, which works in the data link layer. On the other hand, the DHCP is determined to be
highly vulnerable to various attacks like DHCP starvation attack, DHCP rouge server attack,
and malicious DHCP client attacks. This has led to the development of Secure DHCP (S-
DHCP), which is a new scheme that helps in securing the DHCP protocol. This proves that
the DHCP need to be secured well with an effective approach.
As per (Scott and Laws, 2010), the industries of network services ensures that the
networks be to a major study as it provides common features of network services. The
network service specifically depend on other people’s suggestions to direct their customers to
a certain business, because it is difficult to know about the company’s competitors or
customers. Therefore, information exchange is needed through the knowledge network. The
network services require people for engaging their organization’s production, and thus it
maximizes the number of small companies in this industry. Moreover, with the increase of
number also the complexity increases when it involves people in it. Thus, it makes networks
service significant part of networking.
According to (Liu et al., 2018), at present the SDN (Software-Defined Networking) is
a popular talk in the field, as it is known for the future network development. SDN is
expected to implement various control plane and data plane layers. To manage the network
administration issues, the best option that is available today is known to be SDN. It offers
programmability, and it better than the traditional network. The implementation of SDN is
said to improve the traditional network’s functioning, but it is observed to have increased
network attack nodes. Therefore, it end ups to have new security problems.
It is stated by (Courcoubetis and Weber, 2012) that, to design and manage any shared
infrastructure, an individual should consider the fact its participants would make self-
interested and strategic decisions in terms of their desired resources contribution or cost
sharing that they can manage.
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As per (Parmar, 2015), it is determined that the firewall is essential for any network to
secure it from the unauthorized and malicious access of the attackers who intend to harm the
users. Thus, the firewall offers security features. The researcher talks about keeping the
systems updated is necessary, so the end users must install antivirus and take necessary steps
to be safe. On the other hand, the firewall also has the capacity of controlling the flow of
traffic in the internet.
2.1 Summary
From the literature review it is evident that the network system administration is a
challenging task, because the protocols like DHCP is vulnerable to attacks. Therefore, the
network and their users must have enough knowledge to secure their network. The future
network development like SDN’s benefits are discussed which is expected to help the
network system administrator’s issues in managing the network. On the other hand, this
study helps to understand that for designing and manage any shared infrastructure, an
individual should consider the fact that its participants would make self-interested and
strategic decisions in terms of their desired resources contribution or cost sharing that they
can manage. Finally, the topic of firewall mechanism is said where it tells the firewall’s
importance for any network to secure it from the unauthorized and malicious access of the
attackers, who intend to harm the users.
3. Scope and Limitations of the Project
This project’s scope is to effectively manage the responsibility of the network systems
administrator, which includes responsibility of monitoring and taking care of the daily
updates and daily network operations to help the organization work effectively.
Limitations of this project are listed below:
i. Failure of data communication.
ii. Risk security
iii. Expensive set-up
iv. Professional support
4. Proposed Network Design
The existing system is improved with the following proposed network design.
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Figure 1: Proposed Network Design to be implemented
The above network design demands installation and configuration of the following:
 DNS server
 DHCP server
 Client/server
 SSH securing
 iptables firewall
 Real host
 Virtual host
5. Experimental Work & Analysis
Ubuntu is utilized for examining the existing network system services.
5.1 Installation and Configuration of DHCP Server
Use the command shown below to install DHCP server in Linux system:
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Restart DHCP Server
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Use the command shown below and Type open DHCP configuration file:
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Use the command shown below to make changes in the DHCP configuration file.
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Then, in DCHP configuration add the net mask address.
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Use the command shown below to start DHCP server, followed by checking the IP address.
Verify if DHCP is working by utilizing nslookup method. Utilize the following steps:
From the above followed steps it is evident that the DHCP server has been installed in a
Linux system.
5.2 DNS Server in Virtual Machine
Installation Steps for DNS server
Start with an updated Ubuntu virtual machine and finish the installation.
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Use the below shown screenshots to configure DNS server.
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Steps to Configure Primary DNS Server
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\
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Steps to Check BIND Configuring Syntax
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Steps to Restart BIND
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Steps to Configure Secondary DNS Server
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Steps to Configure DNS Clients
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Steps to Test DNS Client
Forward zone
Reverse Zone
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Follow these steps to test DNS configuration file.
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5.3 Real Host and Virtual Host Set-up
Installation Steps for Apache Web Server
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Next step requires creating a new virtual host file.
Then, copy the same in the first domain.
# sudo cp /etc/apache2/sites-available/000-default.conf
/etc/apache2/sites-available/ubuntu.biz.conf
Take help of nano and open the new file.
# sudo nano /etc/apache2/sites-available/ubuntu.biz.conf
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Then in a configuration file go and perform the necessary modifications, and don’t forget to
save.
In the web browser copy the provided link-
The result is shown in the above figure, where it is displayed that the virtual host is working.
In the web browser copy the provided link https://debian.edu.
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The result is shown in the above figure, where it is displayed that the virtual host is working.
5.4 Client/Server Configuration and Interactions
Configuration Steps of DNS Clients
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5.5 Quality of Service Implementation
The ports inherits QoS policies, if they have no other policies to be followed.
Create bw-limiter in an admin tenant.
Configure the policy rules of bw-limiter.
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Configure the neutron port and implement the bw-limiter policy.
Make use of the following command and continue QoS rule review.
5.6 Securing SSH
Installation Steps for SSH
Start installation with an updated Ubuntu virtual system.
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Configuration steps for SSH
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5.7 iptables
Make use of the below provided commands to view the rules of the current iptables.
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The iptables supports in adding the permitted inbound traffic rules. Further, it even
supports to track the connection status. Utilize the commands that you see in the following
screenshot and establish the connection.
Opt package, iptables-persistant, as it helps to make the rules permanent. Also, it will
make sure that the iptables are restored and saved correctly.
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Enter on Yes, as it saves the configuration of the package.
6. Testing and Evaluation
Testing and Evaluating DNS
The Forward zone is shown below.
The Reverse Zone is shown below.
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Follow the screenshots to complete the testing of DNS configuration file.
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Troubleshooting the Issues of DHCP
Follow the screenshots to complete the testing of DHCP client and server.
Verify if DHCP is working by utilizing nslookup method. Utilize the following steps:
From the above followed steps it is evident that the DHCP server has been installed in a
Linux system.
Steps to test Virtual Server
Further, move on and examine the essential tests like if the virtual hosts are in
working form or not. The ping command mentioned below can be helpful to test this.
In the web browser copy the provided link,
The result is shown in the below figure, where it is displayed that the virtual host is working.
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In the web browser copy the provided link- https://debian.edu.
The result is shown in the above figure, where it is displayed that the virtual host is working.
7. Conclusion
This report has helped to understand that the network could come across various
issues like network connectivity issues and performance relate issues. The other thing noticed
is that the key culprits for these issues are DNS and DHCP, which are tested and evalauted.
The network system administration is required to take care of the daily network operations
like organizing, installing, and supporting the systems of any organization, along with the
LANs, WANs, intranets, network segments, and various data communication systems. This
job definitely requires a responsible monitoring to ensure everything is fine, if not it can
create chaos in the organization. Additionally, the existing system protocols might also need
proper configuration. In this report, the proposed network system design is implemented,
where the Linux network services are installed and configured. The firewall mechanism is
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used for network security from the hackers and other unauthorized access. And the virtual
hosts are shown to be working fine from the conducted tests. Hence the troubleshooting is
completed and the results are determined. Henceforth, any network could face network
connectivity issues or performance based issues and it must be monitored effectively.
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References
Courcoubetis, C. and Weber, R., 2012. Economic Issues in Shared
Infrastructures. IEEE/ACM Transactions on Networking, 20(2), pp.594-595.
J. Shimonski, R., 2009. Top 5 Networking Issues With Windows Clients. [online] TechGenix.
Available at: <http://techgenix.com/top-5-networking-issues-windows-clients/> [Accessed 16
April 2020].
Liu, Y., Zhao, B., Zhao, P., Fan, P. and Liu, H., 2018. A Survey Architecture Interface and
Security Issues in Software Defined Networking. International Journal of Recent Trends in
Engineering and Research, pp.1-8.
Parmar, M., 2015. Firewall: A Security Point of a Network. International Journal of Science
and Research (IJSR), 4(12), pp.1568-1570.
Scott, N. and Laws, E., 2010. Advances in service networks research. The Service Industries
Journal, 30(10), pp.1581-1592.
Younes, O., 2016. A Secure DHCP Protocol to Mitigate LAN Attacks. Journal of Computer
and Communications, 04(01), pp.39-50.
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