♻️ Complete Guide to Redirects in Apache

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Properly managing redirects in Apache is a fundamental aspect of website administration. Whether it's changing URL structures, migrating a domain, improving security with HTTPS, or preserving search engine rankings, redirects allow you to guide users and crawlers to the right resources seamlessly.

In this guide, we'll look in detail at how redirects work in Apache and how to write them correctly, from the simplest solutions to the most advanced cases, explaining each step without taking anything for granted.

  1. What are redirects and why are they important?
  2. Where to write redirect rules?
  3. Simple redirects with mod_alias
  4. Advanced redirects (or rewrite rules) with mod_rewrite
  5. Flags: what they are and why they matter
  6. Common mistakes (and why they happen)
  7. Verifying that redirects are working correctly
  8. When to use what

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1. What are redirects and why are they important?

A redirect is an instruction that tells the server:

"The resource you are looking for is no longer here, go to this other address."

When a browser (or search engine) requests a page, Apache can respond in two ways:

  • Serving the content
  • Redirecting the request to another URL

Redirects are essential for:

  • Avoiding 404 errors
  • Maintaining SEO positioning
  • Managing domain or structure changes
  • Forcing HTTPS or a canonical version of the site

2. Where redirect rules are written

Apache reads redirect rules at various points in its configuration.

2.1 .htaccess File

This is the most used file because:

  • It works without server access
  • It is supported by almost all hosting providers

Features:

  • It is read on every request
  • It is slower than the global configuration
  • It applies to the directory it is in and all subdirectories

Example path:

/var/www/html/.htaccess

2.2 Apache configuration file

  • httpd.conf
  • apache2.conf
  • <VirtualHost>

Advantages:

  • faster
  • safer
  • recommended in professional environments

Disadvantage:

  • requires root access
  • often not available on shared hosting

3. Simple Redirects with mod_alias

mod_alias is an Apache module designed for direct, linear redirects, without conditions or complex logic.

3.1 301 Redirect (Permanent)

301 Redirect /old-page.html https://www.site.it/new-page.html

What does it mean?

  • /old-page.html → relative path
  • https://www.site.it/new-page.html → final URL
  • 301 → move permanent

Effects:

  • Browsers update saved links
  • Google transfers SEO authority

3.2 302 Redirect (temporary)

Redirect 302 /promo.html https://www.sito.it/landing.html

Key difference:

  • 301 = “I will never come back here”
  • 302 = “I will come back here later”

Search engines don't transfer rankings with a 302, but they can penalize them.

3.3 Redirecting an entire directory

301 Redirect /blog https://www.sito.it/articoli

What happens:

  • /blog/post1 → /articoli/post1
  • /blog/2023/ → /articoli/2023/

Apache automatically preserves the rest of the path.


4. Advanced Redirects (or Rewrite rules) with mod_rewrite

When logic is needed, mod_alias isn't enough.
This is where mod_rewrite comes in, based on regular expressions.

4.1 Enabling the Rewrite Engine

RewriteEngine On

Without this line:

  • All RewriteRule rules are ignored

4.2 How a RewriteRule Works

RewriteCond # condition (optional)
RewriteRule # true rule and own

Apache:

  1. Reads the requested URL
  2. Checks the conditions
  3. Applies the rule if the pattern matches

4.3 301 Redirect with mod_rewrite

RewriteRule ^old-page\.html$ https://www.sito.it/new-page.html [R=301,L]

Detailed explanation

  • ^ → start of string
  • old-page\.html → escape the dot
  • $ → end of string
  • R=301 → permanent redirect
  • L → stop here, don't read any more rules

4.4 Redirect from HTTP to HTTPS

RewriteCond %{HTTPS} off
RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]

Explanation:

  • %{HTTPS} off → the request is not secure
  • %{HTTP_HOST} → the requested domain
  • %{REQUEST_URI} → the full path

Result:

http://sito.it/pagina → https://sito.it/pagina

4.5 Redirect www → non-www

RewriteCond %{HTTP_HOST} ^www\.sito\.it$ [NC]
RewriteRule ^ https://sito.it%{REQUEST_URI} [R=301,L]

NC = non-case sensitive.
This is used to avoid problems with uppercase/lowercase letters.

4.6 Change URL Structure

RewriteRule ^articles/(.*)$ https://www.sito.it/blog/$1 [R=301,L]
  • (.*) captures anything
  • $1 reinserts it into the new URL

Example:

/articles/seo/apache → /blog/seo/apache

5. Flags: What They Are and Why They Matter

Flags modify the behavior of the rule.

Flags Explanation
R Force redirect
  R=301   Permanent redirect
L Last rule
NC Ignore capitalization
QSA Holds query string  
F Block access (403)

Example with query string:

RewriteRule ^page$ new-page [R=301,L,QSA]

6. Common Errors (and Why They Happen)

Redirect Loops

This happens when:

  • A rule redirects to itself
  • A RewriteCond control is missing

Result:

ERR_TOO_MANY_REDIRECTS

Forgetting RewriteEngine On

Apache reads the rule but doesn't execute it.

Using 302 instead of 301

Very common and very harmful to SEO.

Don't escape characters Special

. ? + ( ) have special meaning in regexes.


7. Verify that redirects are working correctly

After writing redirect rules, it's essential to verify them. A syntactically correct rule can still produce incorrect behavior, such as infinite loops, multiple redirects, or incorrect status codes. For this reason, it is advisable to perform multiple types of tests: syntactic and functional.

7.1 Checking Apache Configuration Syntax

If you have access to the server (VPS or dedicated), Apache provides an official tool to check the correctness of the configuration files:

apachectl configtest

On some distributions, the command may be:

apache2ctl configtest

What this command does:

  • Checks the syntax of all Apache configuration files
  • Verifies that the directives are valid
  • Reports errors, indicating the file and file number line

If everything is correct, the result will be:

Syntax OK

If an error occurs, Apache will display a detailed message, which is useful for quickly identifying the problem.

AH00526: Syntax error on line 12 of /etc/apache2/sites-enabled/000-default.conf

7.1.1. Limitations for the .htaccess file

Verifying a .htaccess file has some important limitations you should be aware of. Unlike Apache's core configuration files, the .htaccess file cannot be validated completely independently.

This is because .htaccess:

  • It is interpreted by Apache only at runtime, when a real request arrives
  • It depends on the context of the directory it is in
  • It requires that necessary modules (such as mod_rewrite) be enabled
  • It is subject to the server's AllowOverride directives

There is therefore no true standalone “lint” that can fully verify a .htaccess file on its own.

Recommended method for verification:

  1. Upload the .htaccess file to the correct directory
  2. Make a request to one of the affected URLs
  3. Check the Apache error logs

Example command to monitor the logs:

tail -f /var/log/apache2/error.log

If errors occur, Apache will display messages like:

RewriteRule: bad flag delimiters
RewriteCond: invalid condition

These messages indicate that the file was read but contains syntax errors or invalid directives.

If no errors appear in the logs and the site behaves correctly, the .htaccess file can be considered syntactically valid and functional.

7.2 Checking via Browser (DevTools)

The simplest and most immediate method to test a redirect is to use the browser's development tools (in this case, we're talking about functional testing, not syntactic testing).

General procedure:

  1. Open the page in the browser (Chrome, Firefox, Edge)
  2. Open the DevTools (F12)
  3. Go to the Network section
  4. Reload the page

What to check:

  • Status code (301, 302, etc.)
  • Header Location
  • Any multiple redirects in cascade

This method is particularly useful for identifying:

  • redirect loops
  • unwanted redirects
  • incorrect status codes (e.g., 302 instead of 301)

7.3 Terminal Testing with curl

For a more technical and precise test, you can use curl:

curl -I https://www.sito.it/vecchia-pagina.html

A correct redirect should return something like this:

HTTP/1.1 301 Moved Permanently
Location: https://www.sito.it/nuova-pagina.html

This method is very Useful because:

  • It does not depend on the browser cache
  • It only displays headers and status codes
  • It is ideal for automated tests or quick checks

7.4 Online Tools for Checking Redirects

There are several online tools that allow you to analyze a URL's redirects. These tools are useful for:

  • Viewing the complete redirect chain
  • Identifying multiple or useless redirects
  • Checking the returned status code

Tool Limitationsnline:

  • They do not verify the actual Apache syntax
  • They do not know the active modules on the server
  • They cannot validate a .htaccess file

They should therefore be considered support tools, not definitive verification.

Below is a list of some of the most commonly used tools:

  • HTTP Status – Checks the complete redirect chain and displays the HTTP headers for each step.
  • Redirect Checker – Allows you to enter a URL and see all the redirects to the final destination.
  • Webconfs Redirect Checker – Analyzes 301, 302, and 307 redirects, displaying the status code and destination.
  • SEO Review Tools – Redirect Checker – Designed for SEO, it displays the redirect path and helps identify multiple or incorrect redirects.

Note

These tools are very useful for checking the behavior of redirects for users and search engines, but they do not replace direct verification on Apache, nor can they validate the syntax of a file .htaccess.

7.5 Recommended Best Practices

The correct verification flow should be:

  1. Syntactic check of the configuration (when possible)
  2. Test the redirect with browsers and DevTools
  3. Technical verification with curl
  4. Final analysis with online tools

Following all these steps dramatically reduces the risk of errors in production and ensures correct redirects for both users and search engines.


8. When to use what

Situation Solution
Single redirect
(simple and precise)		 Redirect
Conditions or regexes mod_rewrite
SEO Migration 301
Temporary tests 302
HTTPS / WWW mod_rewrite

Conclusion

Writing redirects in Apache is not difficult, but:

  • You need to understand the execution order
  • You need to choose the right module
  • You need to test each case


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