<div>
Are you talking about for user who uses it?<br />
Sfw is how you can manage firewall on Ubuntu.<br />
<br />
You did say Desktop.<br />
It is not being used as a server.
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<div>
Yes it's ubuntu desktop version<br />
nextcloud server running on it<br />
so i need to secure it to allow only http and https for users
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<div>
I am unclear which users you are talking about.<br />
User who directly use the desktop to access external resources? What other restrictions or on whom are you looking to impose?
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<div>
<blockquote>
User who directly use the desktop to access external resources?
</blockquote>
 no<br />
&nbsp;<br />
I am talking about users who access nextcloud which installed on ubuntu desktop via internet <br />
the ubuntu desktop acting as a webapp
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<div>
Next loud is access by web http/HTTPS to files in there<br />
<br />
you can use mxtoolbox.com tools to scan your wan ip to see which ports are exposed to the Internet.
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<div>
1) You'll do this using iptables or some other tool which interacts with iptables.<br />
<br />
2) You must be careful. If you only allow HTTP + HTTPS you will have no Web access, as you must also allow port 53 looks for DNS.<br />
<br />
3) There are other ports which may also require special attention, like port 587 if you're submitting email or port 993 if you're accessing email in certain ways.<br />
<br />
4) If you're unused to doing port scans, provide your IP for someone to do an nmap scan for you, then post the results.
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Temody Mas

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<div class="content wysiwyg-content">
Hello EE,<br />
I have Ubuntu 18.0.4 TLS with latest upgrade<br />
I need to secure my OS (hardening) to allow only http and https I/O operations and disable anything else <br />
like ping reply etc
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</div>


Hello EE,
I have Ubuntu 18.0.4 TLS with latest upgrade
I need to secure my OS (hardening) to allow only http and https I/O operations and disable anything else 
like ping reply etc

Secure Ubuntu Desktop (hardening)

Linux is a UNIX-like open source operating system with hundreds of distinct distributions, including: Fedora, openSUSE, Ubuntu, Debian, Slackware, Gentoo, CentOS, and Arch Linux. Linux is generally associated with web and database servers, but has become popular in many niche industries and applications.

Linux

The Linux operating system, in all its flavors, has its own share of security flaws that allow intrusions, but there are various mechanisms by which these flaws can be removed, generally divided into two parts: authentication and access control. Authentication is responsible for ensuring that a user requesting access to the system is really the user with the account, while access control is responsible for controlling which resources each account has access to and what kind of access is permitted.

Linux Security

The cyber security specialization covers the fundamental concepts underlying the construction of secure systems, from the hardware to the software to the human-computer interface, with the use of cryptography to secure interactions. Cyber security refers to the protection of personal or organizational information or information resources from unauthorized access, attacks, theft, or data damage. This includes controlling physical access to the hardware, as well as protecting against the harm that may come via network access, data and code injection, and due to malpractice by operators, whether intentional, accidental, or due to them being tricked into deviating from secure procedures.

Cyber Security

The variety of Linux distributions creates myriad issues relating to configuration and operations when computers are networked, not the least of which is the use of various network management applications, some of which are included with specific distributions, while others are standalone applications.

Linux Networking

Security is the protection of information systems from theft or damage to the hardware, the software, and the information on them, as well as from disruption or misdirection of the services they provide. The main goal of security is protecting assets, and an asset is anything of value and worthy of protection.  Information Security is a discipline of protecting information assets from threats through safeguards to achieve the objectives of confidentiality, integrity, and availability or CIA for short. On the other hand, disclosure, alteration, and disruption (DAD) compromise the security objectives.