Calibre Server Access Issue: IPv6 Loopback Works, but not IPv4 on Windows 11 Pro

Title: IPv6 Loopback Works, not IPv4 in Windows 11 Pro

Introduction

In this article, we will discuss the issue of IPv6 loopback working fine, but IPv4 not working in Windows 11 Pro. We will provide a detailed context of the topic, covering key concepts, subtitles, and paragraphs using the <p></p> tags. We will also include code blocks, enclosed within <code> tags. The content inside the code blocks must be properly formatted according to the programming language, including indentation and tabulation as needed. We will exclude the H1 tag title, as it will be provided separately.

Understanding the Issue

When running Calibre server on a laptop with Windows 11 Pro, the IPv6 loopback works fine at http://[::1]:8080/. However, the IPv4 loopback at http://127.0.0.1:8080/ fails with an error: "Can't reach page, connection reset". Similarly, accessing the server at http://192.168.1.135:8080/ also fails with an error: "Can't reach".

Troubleshooting IPv4

To troubleshoot the IPv4 issue, we need to check the network settings, host file, and firewall settings.

Check Network Settings

1. Open the Control Panel.
2. Click on Network and Internet > Network and Sharing Center.
3. Click on Change adapter settings on the left.
4. Right-click on your network connection and select Properties.
5. Ensure IPv4 is enabled and the IP address and subnet mask are correctly configured.

Check Host File

1. Open Notepad as an administrator.
2. Go to File > Open.
3. Type C:\Windows\System32\drivers\etc\hosts and click Open.
4. Ensure there are no entries that could be causing the issue.

Check Firewall Settings

1. Open Windows Defender Firewall with Advanced Security.
2. In the left pane, click on Inbound Rules.
3. In the Actions pane, click on New Rule.
4. Select Port and click Next.
5. Select TCP and specify the port number (8080 in this case) and click Next.
6. Select Allow the connection and click Next.
7. Add a name for the rule and click Finish.

Repeat the same steps for outbound rules.

Conclusion

By checking the network settings, host file, and firewall settings, we can troubleshoot the IPv4 issue in Windows 11 Pro. If the problem persists, further investigation may be required, such as checking the server logs or network hardware.

References

• Calibre User Manual
• Windows 11 Network Troubleshooting
• Configuring Windows Defender Firewall with Advanced Security