Your website can have a shared IP Address: The Dangers of Shared Hosting

After setting up a website with a trusted hosting provider and securing it with HTTPS, it’s natural to assume your website is airtight. However, if your site is hosted on a shared IP address, it could be coexisting with dozens or even hundreds of other websites, some of which may be compromised, hosting malware, or blacklisted. In such cases, a security breach on one of those websites could indirectly affect your own, putting your reputation and visibility at risk.

To maintain a resilient and reputable online presence, it’s crucial to assess the risks of shared IP hosting and explore ways to strengthen your setup. If necessary, you can switch to a dedicated IP using different techniques. Many hosting providers allow users to request a dedicated IP, and this article will outline how to do that, along with insights into choosing the right hosting option.

Yes, Your IP address may not be as secure as it appears.

In this article, we will explore:

• A Try Now option to check if your website is using a shared IP address.

• The process of how a shared IP hosting works.
• The security risks and hidden dangers associated with shared IP hosting such as IP blacklisting, cross-site contamination, and server misconfigurations.
• Practical steps to strengthen your website’s defences, with sample code and configuration tips.

Check if Your Website Shares an IP Address

Want to know if your website shares its IP address with other domains?

The first step toward making smarter hosting decisions is knowing who else shares your IP address. Use our tool to instantly check which other websites are hosted on the same IP as yours. This simple check can help you identify potential exposure to malicious neighbors that could affect your site’s reputation, deliverability, or even its search rankings.

Just enter your domain name and see the results for yourself.

How Shared IP Hosting Works (A Behind-the-Scenes Look)

A shared IP hosting environment allows multiple websites to operate under a single public IP address. Hosting providers do this to conserve resources, much like an apartment complex where different residents (websites) share the same building address (IP) but have unique room numbers (domain names). Let’s begin by understanding why shared IP environments require closer attention. Here’s what happens behind the scenes:

1. Single IP, Multiple Websites

Since multiple websites share the same IP, the server must differentiate them when handling requests. This is done using several key mechanisms:

Host Header (For HTTP Requests):

• When a browser sends a request, it includes the domain name in the Host header.
• Web servers like Apache and Nginx use this to determine which website to serve.

GET / HTTP/1.1
Host: example.com

The server reads example.com and serves its files. If another user requests anotherwebsite.com, the server reads that domain and serves its respective content.

2. X-Forwarded-Host (For Reverse Proxy Setups)

• When a website is behind a reverse proxy (e.g., Cloudflare, AWS Load Balancer), the original Host header might get altered.
• Reverse proxies act as intermediaries and forward the actual domain name using the X-Forwarded-Host header, which the backend server (e.g., Apache, Nginx) uses to determine which website to load.

X-Forwarded-Host: example.com
This ensures that the correct website is served even if the request goes through an intermediary.

3. Server Name Indication (For HTTPS Requests)

• When a browser requests a website over HTTPS, it includes the domain name in the SSL/TLS handshake using Server Name Indication (SNI).
• This allows the server to serve the correct SSL certificate for each website, even when using the same IP.

Client Hello
SNI: example.com
The server sees "example.com" and presents the correct SSL certificate.

4. How Requests Are Handled in Shared Hosting

• A user types example.com in their browser.
• The DNS system translates the domain into the shared IP.
• The request reaches the web server or reverse proxy.
• The server reads the Host, X-Forwarded-Host, or SNI headers.
• The correct website’s files are loaded and served.
• If someone else types anotherwebsite.com, the process repeats, ensuring each user gets the website they requested, all while using the same shared IP.

Shared IP hosting is efficient, but it requires careful handling to ensure websites function correctly.

Security Risks of Shared IP Hosting

This shared infrastructure means your website’s security is not solely in your control, it’s also influenced by the behavior and vulnerabilities of other websites on the same IP.

If even one site is compromised, it can potentially impact the others in several ways, including:

1. IP Blacklisting

• If a website on the shared IP is flagged for spam, phishing, or malware, email servers and security tools may blacklist the entire IP address.
• This means that even if your site is legitimate, emails sent from your server could be marked as spam or blocked entirely.
• Many email providers, including Gmail and Outlook, use these blacklists to filter out potentially harmful messages, which can significantly impact your website’s reputation and email deliverability.
• Aside from email, search engines may lower trust signals or crawling frequency for domains on blacklisted or spam-associated IPs, especially if abusive activity is ongoing.

Example: Email Deliverability Issue

Let’s say a spammer is on the same shared IP. Email providers might blacklist the IP, meaning:

• Your legitimate business emails could land in spam.
• You might not even know this is happening.
• Your email reputation suffers.

curl -s https://api.abuseipdb.com/api/v2/check?ipAddress=YOUR_IP \
  -H "Key: YOUR_API_KEY" \
  -H "Accept: application/json"
  

This checks if your IP is blacklisted for malicious activity.

2. Cross-Site Contamination

Malwares can spread from one infected website to others on the same server. If one site on a shared IP gets compromised, attackers may exploit vulnerabilities in a single website to gain access to the entire shared hosting environment.

Example: PHP Backdoor via a Compromised Site

A vulnerable WordPress site on the shared IP gets infected with a simple backdoor:

The attacker can now:

• Modify files of other websites.
• Steal database credentials.
• Redirect traffic to phishing sites.

How to Protect Yourself:

• For cloud-hosted websites, many providers offer ways to switch to a dedicated IP. For instance, on Azure, you can use IP-based SSL binding to assign a dedicated IP to your application (Azure Documentation). Similar options are available on AWS, Google Cloud, and other platforms, allowing you to reduce exposure to shared hosting risks.

• Use containerized hosting (e.g., Docker, Kubernetes) to isolate your site from others on the same server.

• Regularly scan for malware using ClamAV: clamscan -r /var/www/

• Even though a dedicated IP gives you more control, it’s not a complete solution. Outdated plugins, weak passwords, or insecure file permissions can still put your site at risk, regardless of the IP.

DDoS Attacks: Your Site Becomes Collateral Damage

If one website on the shared IP becomes the target of a Distributed Denial-of-Service (DDoS) attack, all websites on the same IP could suffer the same including downtime or slow performance.

How to Defend Against This:

• Use Cloudflare or AWS Shield to mitigate DDoS attacks.
• Rate-limit connections:

limit_req_zone $binary_remote_addr zone=one:10m rate=10r/s;

sudo apt install fail2ban

Various Tools to Check If You’re at Risk

When using shared IP hosting, your website isn’t operating in isolation. If another site on the same IP gets blacklisted, compromised, or flagged for malicious activity, your website could suffer collateral damage even if you’ve done nothing wrong.

To assess your risk level, you can use various tools that analyze shared IP security. Here are some of the most useful ones:

ViewDNS.info

Performs reverse IP lookups to check which other websites share your IP. Also provides Whois data and DNS analysis to help you investigate suspicious domains.

AbuseIPDB

A real-time blacklist checker that scans whether your IP address is flagged for spam, malware, or cyber threats.

MXToolbox

Focuses on email security, checking if your IP or domain is blacklisted, which can affect email deliverability.

Shodan

A powerful search engine for internet-connected devices that scans for open ports, exposed services, and potential vulnerabilities linked to your IP.

Best Practices

If you discover suspicious websites sharing your IP, act immediately:

• Switch to a dedicated IP or VPS to isolate your site from bad actors.
• Monitor your site’s security logs for unusual traffic or hacking attempts.
• Use a Web Application Firewall (WAF) to block potential threats.
• Contact your hosting provider to request a different IP address if necessary.

To Conclude

While shared IP hosting can be cost-effective and easy to manage, it often sacrifices security and reliability. Your website’s performance and reputation can be impacted by the actions or vulnerabilities of neighbouring domains. A single compromised domain on the same IP address can expose your site to reputational damage, email deliverability issues, and potential security breaches.

It is important to recognize that IP-based isolation does not guarantee protection. A multi-layered security strategy, combining WAFs, encryption, API security, segmentation, and Zero Trust, is the best way to protect against attacks on shared IP environments.

Businesses and developers must evaluate their hosting environments regularly, consider switching to dedicated IPs when needed, and apply best practices to reduce the impact of shared infrastructure. These foundational elements should be enhanced for overall resilience and to protect both your users and your digital assets.