Ubuntu, one of the most popular Linux distributions, hosts countless websites, applications, and databases. However, many users forget crucial security settings after deploying their servers. While Ubuntu with default configurations is ready to use out of the box, it's far from truly secure. A server neglecting security configurations is like an unlocked house—it's only a matter of time before it's compromised. This article systematically outlines the methods, core steps, and precautions for security settings in an Ubuntu environment, helping you upgrade your server from "usable" to "secure and usable."

Why are Ubuntu security settings essential?

Many novice users have a misconception: that Linux is inherently more secure than Windows and therefore requires no additional configuration. This view is only half true—Linux does have a stricter permission system and fewer malware targets, but default configuration is not the same as secure configuration.

The internet is rife with automated scanning scripts that scan public IPs 24/7, looking for weak SSH passwords, unpatched vulnerabilities, and open sensitive ports. A newly deployed Ubuntu server, if left unattended, could be scanned within minutes and subjected to brute-force attacks within hours.

The core purpose of security settings is not "absolute defense" (that doesn't exist), but rather to increase the cost of attacks—making attackers feel that "it's too difficult to compromise this machine, let's move on to the next one."

Six Core Steps for Ubuntu Security Settings

Step 1: Keep Your System and Kernel Updated

This is the simplest and most important step. Ubuntu continuously releases security updates to fix known vulnerabilities. Failing to update in a timely manner is tantamount to leaving vulnerabilities wide open for attackers.

It is recommended to enable Unattended Upgrades, allowing the system to automatically install security updates. Execute the following commands to enable it:

sudo apt update && sudo apt upgrade -y

sudo apt install unattended-upgrades -y

sudo dpkg-reconfigure --priority=low unattended-upgrades

In the pop-up window, select "Yes," and the system will automatically check for and install security updates daily. This protects the system from known vulnerabilities, preventing software corruption or data loss.

Step Two: SSH Security Hardening – Guarding the First Line of Defense

SSH is the only channel for remotely managing servers and also the most frequent target of attackers. The following configurations are indispensable:

- Disable direct root login: Edit `/etc/ssh/sshd_config` and change `PermitRootLogin` to `no`. Use a regular user login for daily use; use `sudo` only when privilege escalation is needed.

- Disable password login and use key authentication instead: Set `PasswordAuthentication` to `no`. Key authentication is orders of magnitude more secure than passwords; brute-force attacks are ineffective against keys.

- Change the default port: Change `Port 22` to another high-order port (such as `2222` or `10086`). This can filter out 99% of automated scans.

- Configure login failure restrictions: Install `fail2ban` to automatically block IPs that have repeatedly failed to log in.

After making the changes, execute `sudo systemctl restart sshd` to apply the configuration.

Step 3: Configure the Firewall – Open Only the Necessary Ports

Ubuntu's default firewall is `ufw` (Uncomplicated Firewall). The basic principle is "deny by default, allow only what's needed":

sudo ufw default deny incoming

sudo ufw default allow outgoing

sudo ufw allow 2222/tcp # Your new SSH port

sudo ufw allow 80/tcp # HTTP

sudo ufw allow 443/tcp # HTTPS

sudo ufw enable

Only open ports necessary for business operations; close all others. This greatly reduces the attack surface.

Step 4: Manage Users and Permissions – Minimization Principle

- Delete unused default users: such as `games`, `news`, and other system-provided accounts that are not used.

- Configure sudo permissions for ordinary users: Grant only necessary command permissions; do not grant `ALL:ALL`.

- Regularly review the user list: Check `/etc/passwd` and promptly handle any abnormal accounts. Step 5: Install Security Monitoring Tools

- Fail2ban: Monitors log files and automatically blocks malicious IPs, serving as the first line of defense against brute-force attacks.

- Rkhunter / Chkrootkit: Regularly scans for rootkits and backdoor programs.

- AIDE: A file integrity checker that monitors critical system files for tampering.

Step 6: Data Backup – The Last Line of Defense

No matter how good your security settings are, they cannot guarantee 100% protection. Regular backups are the last line of defense against ransomware, accidental data deletion, and system crashes. A "3-2-1 backup strategy" is recommended – 3 copies of data, 2 on different media, and 1 stored off-site.

Common Misconceptions and Avoidance Guide

Misconception 1: Turning off the firewall is enough.

Some users find configuring firewalls too troublesome and simply turn them off. This is equivalent to exposing the server to arbitrary scanning on the public internet. A firewall is a necessity, not an option.

Myth 2: A complex password equals security

Even the most complex password can't withstand brute-force attacks and social engineering attacks. Key authentication + disabling password login is the correct approach to SSH security.

Myth 3: Install and forget, never check

Security configuration is not a one-time task. It is recommended to check system logs, user lists, open ports, and update status at least once a month.

Myth 4: Ignoring cloud service provider security recommendations

Different cloud service providers may have specific security best practices. For example, providers like Jtti often provide system update assistance and security advice to help users reduce security vulnerabilities. Utilizing these resources effectively can be much more efficient.

Why choose Jtti to deploy your Ubuntu environment?

Security settings require a stable, reliable, and high-quality network infrastructure. Jtti (JT TELECOM INTERNATIONAL PTE.LTD) is a Singapore-based global network infrastructure service provider, offering one-stop internet service solutions including cloud servers, server leasing, hosting, and security technology development.

Jtti's core advantages include:

- Global Backbone Network: Deployed multiple T3+ level data centers in Hong Kong, the United States, Singapore, and other locations, with over 5,000 dedicated servers.

- Premium CN2 GIA Bandwidth: All cloud server packages are equipped with CN2 GIA bandwidth, offering unlimited traffic. Whether serving users in mainland China, Southeast Asia, or North America, users can enjoy a low-latency, highly stable network experience.

- No Real-Name Registration Required: Supports purchase without real-name registration; ready to use immediately.

- Professional Technical Support: 80% of team members have over 10 years of industry experience, providing 24/7 technical support.

- Security Service System: Jtti not only provides infrastructure but also additional security services, including SSL certificates and top-level domains, preparing for the long-term secure expansion of your business.

Whether you are an individual developer, a cross-border e-commerce practitioner, or a small and medium-sized enterprise, Jtti's Ubuntu cloud server environment lays a solid foundation for your subsequent security configuration.

Ubuntu security setup is not a one-time task but a continuous iterative process. From system updates, SSH hardening, and firewall configuration to access control and regular backups, every step enhances server security. Remember: security is not a state, but a process.

If your Ubuntu server hasn't yet completed the above configurations, we recommend starting today—first update your system, then harden your SSH, and then configure your firewall. Take it one step at a time, and your server will become increasingly secure. Choosing a cloud service provider like Jtti, with its global backbone network and professional technical support, will ensure a more stable and sustainable security journey.