Problem: Confusion Between .CER and .CRT Files
When setting up SSL certificates for Apache servers, users often get confused about the differences between .CER and .CRT file extensions. This confusion can cause problems in configuring SSL certificates, which may lead to security issues or server errors.
The Answer: Interchangeability of .CER and .CRT Files
Functional Equivalence
.CER and .CRT files are the same in their content. Both file types contain public key certificates used in SSL/TLS. The main difference is their name, not their content or function.
In Apache SSL setups, you can use .CER or .CRT files interchangeably. The server recognizes the file content, not the extension. When setting up your Apache server, you can rename your .CER file to .CRT if your setup needs a .CRT file, or you can change your Apache setup to use the .CER file directly.
Tip: Renaming Certificate Files
When renaming certificate files, make sure to update any references to the file in your Apache configuration. For example, if you rename "mycert.cer" to "mycert.crt", update your SSL configuration to reflect this change:
SSLCertificateFile /path/to/mycert.crtWindows-Specific Differences
While .CER and .CRT files are the same, Windows handles them differently when you double-click them:
-
.CER files: Double-clicking a .CER file in Windows opens the certificate viewer. This lets you see the certificate's details without adding it to the system's certificate store.
-
.CRT files: Double-clicking a .CRT file in Windows usually asks you to add the certificate to the Windows certificate store. This is designed for quick setup of trusted certificates.
These differences only affect how Windows handles the files when you use them on the operating system. They do not change how Apache or other web servers use these files for SSL setup.
