As of 2024, there are about 35 billion recorded data breaches, among other types of cyberattacks online. As businesses become increasingly interconnected through the internet, proactive security measures, including IP blocking, become more crucial. 

Thousands of new malicious IP addresses are identified each year, making it imperative to stay ahead of potential threats by implementing effective IP-blocking strategies. 

This guide is going to help you understand what IP addresses are, why it’s sometimes necessary to block them, and how you can do it on various devices and platforms. 

How to block an IP address 

It’s essential to learn how to protect yourself from external threats. The basic security offered by internet servers can ward off some infiltration attempts, but often crafty criminals slip through the cracks. 

Learning how to identify and block the IP address of malicious entities is one of the best ways to improve your security on the internet. 

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What is an IP address? 

An Internet Protocol (IP) address is a unique numeric identifier assigned to each device connected to a network. It can be compared to a home address but for your phones or laptops connected to the internet. Each device is assigned a unique IP address that allows it to interact with, receive information from, and otherwise contact other devices and networks on the internet. 

What do IP addresses look like? 

Even though most internet users connect to the internet using an IP address daily, the majority don’t know what an IP address looks like. 

It can take two forms: IPv4, which stands for “Internet Protocol version 4.” and IPv6, which stands for “Internet Protocol version 6.” 

IPv4 

Invented all the way back in the 70s, IPv4 was the first wave of IP addresses. Generally, IPv4 addresses are composed of four numbers between 0-255, separated by dots or periods. It may look like: 99.31.235.187. 

Since the early days of the internet, IP addresses were assigned using the IPv4 model. But we’ve used up all available IPv4 addresses, which has led us to adopt IPv6. While most devices still use IPv4 to connect to the internet, the shift toward IPv6 began in earnest in 2011 when it was officially launched. 

IPv6 

On June 6, 2012, IPv6 was launched by organizations like the Internet Society and major internet service providers to accommodate the growing number of devices online. They made sure the number of conceivable IPv6 addresses is enormous and won’t run out anytime soon. 

It uses a hexadecimal digit system, separates groups using colons, and may include letters like 2001:0db8:85a3:0000:0000:8a2e:0370:7334. 

Why do you need to block IP addresses? 

A business, educational institution, or internet user would attempt to block specific IP addresses for several reasons. In general, the most common reasons are: 

• Blocking bots, spammers, and hackers. When bots, spammers, and hackers attempt to infiltrate your website, it can strain your bandwidth and decrease the speed with which you and other users can access your website. If you run a business online, this can be detrimental to sales.  

• Limiting website access. Many academic institutions and businesses use IP blocking to restrict the websites that students or employees can visit. The goal is typically to increase productivity by limiting distractions. 

• Protecting data. Hackers often attempt to infiltrate websites to steal data or other vital information. That information can be used to blackmail or otherwise undermine a company. 

• Maintaining confidentiality. Many academic institutions and companies that keep sensitive records—like transcripts, health records, etc.—are regularly targeted by hackers. Identifying malicious IP addresses and placing them on a blocklist is essential to keep those records safe and confidential. 

• Controlling traffic. It helps manage traffic to a website or network by restricting access from specific locations or known problematic IPs, which can improve website performance and reduce server load. 

• Enhancing privacy. Blocking IPs can be a method to prevent stalking, harassment, or other privacy intrusions, mainly if these issues are traced back to specific IP addresses. 

• Complying with legalities. Some businesses may need to block IPs from certain countries or regions due to trade restrictions, copyright laws, or other regulatory compliance requirements. 

How to block an IP address 

This section will cover the steps for blocking an IP address using Mac, Windows, Linux, Router, and Web Hosting. 

Blocking an IP address for Mac users 

To block an IP address on your Mac computer, you’re going to need access to your wireless router (or LAN router, which connects to the internet using an Ethernet cable), as macOS does not provide a straightforward GUI-based method for IP blocking directly on the system. Knowing the password is essential, as it can often be found printed or stuck on the outside of the modem. 

1.) Go to the Apple menu. Find the Apple logo in the top left corner of your computer screen. 

2.) Select system preferences. Open the dropdown menu and select “System Preferences.” Once the menu appears, find the icon labeled “Network.” Press the “Advanced” bar at the bottom of the screen. Navigate to the TCP/IP tab, where you should find your IPv4 or IPv6 address. 

3.) Log in your router. Next, you’re going to have to log into your router. Again, password information can typically be found outside the router, but you can always contact your network administrator if you’re having trouble. 

4.) Restrict access. Once you’ve logged into your router, a list of enabled and disabled IP addresses should appear. From there, most routers will give you the option to deny access to unique IP addresses or an entire range of addresses. You should also have the option to block a website. After blocking the IP address, your network will be protected from that address. 

Blocking an IP address for windows users 

Blocking IP addresses on a Windows computer requires going through the “Windows Firewall.” In tech terms, a firewall is a component that allows your computer to block access to your network without inhibiting your ability to communicate with outside networks. 

1.) Locate website to block. Open your internet browser and locate the website you want to block. Highlight and copy everything that comes after the “www” in the web address. 

2.) Open command prompt. Navigate to your start menu and open “Command Prompt (Admin).”  

Type ping website.com and press Enter. Replace “website.com” with the domain name of the website. The command will display the IP address of the website. Command Prompt should respond by generating several lines of code, which should reveal the website’s IP address. 

Or you can type nslookup website.com. Highlight and copy the IPv4 or IPv6 address.  

Return to your internet browser, paste it into the search bar, and press enter. Confirm that it takes you back to the website.   

3.) Open windows firewall. Open the start menu. Locate “Control Panel.” From there, find “Windows Defender Firewall.” Open it. 

4.) Advanced settings + windows inbound rules. With Windows Firewall open, locate and click on “Advanced settings” on the left of the screen.  

Then, locate “Inbound Rules,” which should also be found near the top left of the screen. This should change the menu options. On the right portion of the window, find and click on “New Rule” 

5.) New rule. With the New Rule tab open, select the “Custom” option and press “Next.”   

Choose All programs to apply the rule to all programs or specify a program path if you want to block the IP for a specific program, then click “Next”. 

6.) Protocol and Ports. Leave the default settings (Any) or specify if needed, then click “Next”. 

7.) Scope. Under “Which remote IP addresses does this rule apply to?”, select “These IP addresses”. Click on “Add” to specify the IP addresses you want to block. You can enter a single IP address, a range, or a subnet. Click “OK” and then “Next”. 

8.) Action. Choose Block the connection and click “Next”. 

9.) Profile. Select when this rule applies (Domain, Private, Public). It’s safe to select all if you are unsure, then click “Next”. 

10.) Name. Give the rule a name and an optional description, then click “Finish”. 

Blocking IP addresses for Linux users 

Linux is a different operating system, so it needs a different process to manage network security, including effectively blocking IP addresses. Here’s how you can do it using iptables: 

1.) Open the Terminal. You can find the Terminal application in your system’s utilities or search for it in your application menu. 

2.) Block with IPTables. Once the Terminal is open, use IPTables, a powerful tool Linux users use to manage network traffic. To block a specific IP address, you enter a command like this: sudo iptables -A INPUT -s [IP address] -j DROP 

In this command, replace [IP address] with the IP address you want to block. Here’s what each part of the command does: 

• Sudo. Runs the command with administrative privileges, ensuring you have the right to modify firewall settings. 

• iptables. The command to modify the firewall rules. 

• -A INPUT. Appends a rule to the input chain, which handles incoming traffic. 

• -s [IP address]. Specifies the source IP address that you want to block. 

• -j DROP. Tells the system to drop packets from the specified source, effectively blocking the IP address from accessing your system. 

Blocking IP addresses for routers 

When you block IPs on your router, you secure all devices on your network by controlling all internet traffic in one place. This is simpler than using command-line tools on systems like Linux and affects more devices. It’s a practical way to improve network security and manage bandwidth. 

Here’s a step-by-step guide to do it through your router’s interface: 

1.) Access the router interface. Start by logging into your router. You can do this through its web interface, which is usually accessed by typing the router’s IP address into the web browser’s address bar. Shared IP addresses for routers are 192.168.1.1 or 192.168.0.1, varying depending on your router manufacturer. You’ll need your username and password, which are often set to default values like ‘admin’ and ‘password’ unless you have changed them. 

2.) Locate IP blocking options. Once logged in, navigate to the router’s security settings. This section might be labeled differently depending on the router’s firmware; look for terms like “Firewall,” “Security,” or “Access Control.” Here, you will find options to manage IP blocking. Enter the certain IP addresses you want to block. Depending on your router’s capabilities, you may be able to block individual IPs or ranges of IPs. 

3.) Entering IP addresses. There should be a field where you can type in the address you want to block. If you want to block multiple IP addresses, you might need to add each separately or specify an IP range. 

4.) Applying and saving changes. After entering the IPs, you can block, apply, or save the changes. You might reset your configurations once you log out or restart the router if you fail to do so. 

Blocking IP addresses for web hosting services 

When you block IP addresses on your web hosting service, it protects your entire website no matter where it gets accessed. It’s a simple and effective way to keep your online services safe and manage who can visit your site from anywhere in the world. It’s more efficient than blocking IPs on your computer or local network, which only protects the devices connected to that network. 

Here’s how to manage IP restrictions through your web hosting control panel: 

1.) Access the hosting control panel. Log into your web hosting control panel. It’s typically accessible through your web hosting provider’s website, where you must enter your username and password. Once logged in, you’ll be directed to your control panel’s dashboard or home page. 

2.) Locate IP blocking tools. Search for the IP blocking feature within your control panel. This may be under sections like “Security,” “Firewall Settings,” or “IP Deny Manager.” The exact naming can vary depending on your control panel, such as cPanel, Plesk, or others. 

3.) Navigating to IP blocking. Once you find the IP blocking section, click on it to open the settings to manage IP restrictions. 

4.) Enter IP addresses to block. In the IP blocking interface, there should be an option to add new IP addresses to the block list. You can typically enter a single IP address or a range of IP addresses to block. 

• Single IP Blocking. If you want to block a specific IP, enter it in the provided field. 

• Range Blocking. To block a range of IPs, you might need to use CIDR notation (like 192.168.1.0/24) or input a start and end IP address, depending on the options provided by your hosting service. 

5.) Apply and save changes. After entering the IP addresses or ranges, you wish to block, save, or apply the changes. There might be a button or link to click that will update the settings. Confirming these changes is crucial to ensure that the IPs are indeed blocked. 

6.) Verify the settings. After blocking the IPs, verifying that the settings are working as intended is a good idea. You can check this by accessing your site from the blocked IP addresses (if you have access to them) or by monitoring access logs for any further activity from those IPs. 

Troubleshooting common IP blocking issues 

You might encounter a few common issues when implementing IP blocks to secure your network or website. Troubleshooting these problems ensures that your security measures don’t block legitimate users or fail to block malicious traffic. Below, we explore some of these typical issues and offer detailed steps to resolve them. 

Blocked IPs are not taking effect. 

Sometimes, even after you set rules to block specific IPs, these blocks are not taking effect. This can leave your network vulnerable, so promptly addressing these issues is crucial. 

• Verify firewall rules. Start by double-checking your firewall settings. Make sure that all configurations are correctly implemented and active. This includes ensuring that the rules are applied to the right network domain and have the correct priority in your firewall’s rule list. 

• Check IP entries. Errors in entering IP addresses are shared. Verify that the IP addresses are correctly formatted and match those intended for blocking. Pay attention to potential typographical errors or misplaced segments in the IP address. 

• Restart equipment. Sometimes, changes may only take effect once the network equipment is restarted. This can apply to both routers and firewalls. A simple reboot can often activate the new settings, making your IP blocks effective. 

Legitimate access blocked 

On occasion, IP blocking can unintentionally affect legitimate users, restricting their access to your network or website, leading to frustration and disrupting business operations. 

• Review the blocklist for errors. Regularly inspect your blocklist for any incorrect entries. This includes checking for IPs that should not have been listed or legitimate IP ranges mistakenly blocked due to an overlap with broader blocked segments. 

• Adjust rules. You may need to adjust your firewall rules if legitimate IPs are blocked. This involves whitelisting certain IP addresses or modifying the criteria to block IPs to be more specific and targeted, preventing overblocking. 

• Check for false positives. Ensure that your security settings are calibrated correctly. Overly aggressive security measures can sometimes block legitimate users, so finding a balance that maintains security without being overly restrictive is essential. 

Difficulty finding IP address 

Identifying the correct IP addresses to block is fundamental to effective network management. If you’re having trouble pinpointing which IPs to block, here are some methods to help: 

• Use online tools. There are numerous tools available online that can resolve domain names to their corresponding IP addresses. These tools can be invaluable when you know the domain but not the IP. 

• Check website logs. Your website’s access logs can provide insights into the traffic it receives. Reviewing these logs allows you to identify potentially malicious activity based on IP addresses and take appropriate action. 

Best practices for blocking IP addresses 

When safeguarding your network through IP blocking, it’s vital to follow a set of best practices to ensure that your efforts are practical and balanced. Proper IP blocklist management and security settings help protect against threats while ensuring legitimate users can access your network without disruptions. Here’s how you can maintain an optimal balance: 

1. Update blocklists. Regularly update your blocklists to reflect the evolving threat landscape. Add new suspicious IPs as threats are identified and remove IPs that no longer pose a risk. 

2. Review security settings. Continually reassess your security protocols to ensure they remain effective against current threats. This includes verifying that your firewall and other security tools are configured correctly and functioning as expected. 

3. Maintain user access. It’s crucial to carefully manage your IP blocking strategies to ensure you don’t accidentally block legitimate users. Regular reviews and adjustments can help prevent such issues. 

4. Use automated tools. Leverage automated systems for managing IP addresses to reduce the likelihood of human error and streamline updating and applying blocklists. 

5. Implement a broader security strategy. View IP blocking as one element of a comprehensive security strategy. This integrates various defensive measures to create a multi-layered defense system. 

6. Enhance with additional measures. Augment IP blocking with additional security measures, such as intrusion detection systems and regular security audits, ensures a thorough and robust protection scheme. 

Why is my IP address blocked? 

A blocked IP address might suddenly no longer access certain websites or services. This could prevent you from using email, streaming content, or even logging into platforms you usually use without problems. 

If your IP was blocked by mistake—something that can happen with shared or dynamic IP addresses—you’ll need to figure out what caused this and talk to your service provider to fix the issue. Here are several potential reasons to help you: 

Viruses in your device 

One of the most common reasons that IP addresses are blocked from accessing remote servers is that the remote server detects a virus within your IP address. Internet users often don’t even know they have picked up a virus. 

Once you’ve removed the virus from your network, feel free to reach out to the website you attempted to access and explain why you should be removed from the blacklist. 

Software extensions 

There are many ways to customize your internet browser. Some of the extensions you can add will eliminate pop-up ads from websites or attempt to detect viruses hiding within a website. 

There’s nothing illegal about adding extensions to your browser, but some websites will ban users who run ad-blockers. They may see this as a disruption of their revenue flow. 

History of illegal activity 

If you have a history of conducting illegal activity online, many website admins will block your IP address as a preventative measure, deeming you untrustworthy. Online illegal activities may include illicit trade, activity on the dark web, or cybercrimes. 

Inappropriate website content 

If you operate a website that contains potentially offensive content like pornographic material or illegal trade, you will likely be blacklisted from many websites because your content is subjectively inappropriate. 

While you may disagree with the decision of another admin to blacklist your website, the only way around the blacklist is a direct appeal to the admin. 

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Recapping how to block an IP address 

Understanding how to block an IP address is crucial for maintaining a secure and trouble-free online experience. IP addresses are fundamental in connecting devices to the internet and locating them among countless others. 

When a device or website causes issues, identifying its IP address lets you take direct action. You can effectively prevent further unwanted interactions by blocking the troublesome IP address through a straightforward process. Enhance your online security while controlling your internet environment. 

Don’t let unwanted online disruptions compromise your safety. Take control today by learning how to identify and block problematic IP addresses. Empower yourself to create a safer and more secure online experience with the right steps and security tools.