Below are some common Apache Web Server configuration directives and their syntaxes:
1. **ServerRoot**:
```
ServerRoot /path/to/server/root
```
2. **Listen** (specify the IP address and port for incoming connections):
```
Listen 80
Listen 192.168.1.100:8080
```
3. **ServerName** (specify the hostname and port for the server):
```
ServerName example.com
ServerName www.example.com:8080
```
4. **DocumentRoot** (specify the directory containing the website files):
```
DocumentRoot /path/to/website/files
```
5. **Directory** (per-directory configuration block):
```
<Directory "/path/to/website/files">
Options Indexes FollowSymLinks
AllowOverride All
Require all granted
</Directory>
```
6. **VirtualHost** (define virtual hosts for hosting multiple websites on the same server):
```
<VirtualHost *:80>
ServerName example.com
DocumentRoot /path/to/website/files
</VirtualHost>
```
7. **Alias** (map URLs to specific directories outside the DocumentRoot):
```
Alias /images/ /path/to/images/
```
8. **ErrorLog** (specify the path to the error log file):
```
ErrorLog /path/to/error/log
```
9. **CustomLog** (define the format and path for access log):
```
CustomLog /path/to/access/log combined
```
10. **DirectoryIndex** (specify the default file to load when accessing a directory):
```
DirectoryIndex index.html index.php
```
11. **RewriteEngine** (enable or disable the URL rewriting engine):
```
RewriteEngine On
```
12. **RewriteRule** (create URL rewriting rules):
```
RewriteRule ^old-page$ /new-page [R=301,L]
```
13. **Redirect** (perform URL redirection):
```
Redirect 301 /old-page http://example.com/new-page
```
14. **ProxyPass** and **ProxyPassReverse** (configure reverse proxy settings):
```
ProxyPass "/api" "http://backend-server/"
ProxyPassReverse "/api" "http://backend-server/"
```
15. **Header** (set custom HTTP headers):
```
Header set X-Custom-Header "Custom Value"
```
Remember to use the appropriate Apache configuration file (e.g., httpd.conf) to include these directives. Always restart or reload the Apache server after making changes to the configuration files.
16. **AllowOverride** (determine which directives are allowed in .htaccess files):
```
AllowOverride All
```
17. **Options** (set various options for directories):
```
Options Indexes FollowSymLinks
```
18. **Require** (specify access control requirements):
```
Require all granted
Require ip 192.168.1.0/24
Require valid-user
```
19. **Limit** (restrict access based on HTTP methods):
```
<Limit GET POST>
Require valid-user
</Limit>
```
20. **AuthType** (set the authentication method):
```
AuthType Basic
```
21. **AuthUserFile** (specify the file containing user and password information for Basic authentication):
```
AuthUserFile /path/to/password/file
```
22. **ErrorDocument** (define custom error pages):
```
ErrorDocument 404 /404.html
ErrorDocument 500 /500.html
```
23. **HeaderName** and **ReadmeName** (set custom names for header and footer files in directory listings):
```
HeaderName header.html
ReadmeName footer.html
```
24. **LogLevel** (set the level of verbosity for error logging):
```
LogLevel warn
```
25. **ProxyPassMatch** (define regex-based reverse proxy settings):
```
ProxyPassMatch "^/(.*\.php(/.*)?)$" "fcgi://localhost:9000/var/www/$1"
```
26. **ServerSignature** (enable or disable server signature in response headers):
```
ServerSignature Off
```
27. **Timeout** (set the maximum time the server will wait for certain operations to complete):
```
Timeout 300
```
28. **KeepAlive** (enable or disable persistent connections):
```
KeepAlive On
KeepAliveTimeout 5
```
29. **DirectoryIndex** (set the default file to load when accessing a directory):
```
DirectoryIndex index.html index.php
```
30. **AddType** (map file extensions to MIME types):
```
AddType application/pdf .pdf
AddType image/jpeg .jpg .jpeg
```
These are just some of the many configuration directives available in Apache Web Server. It's essential to refer to the Apache documentation for detailed explanations of each directive and their usage. Proper configuration is crucial for the security and performance of your web server. Always test your changes and verify that they have the desired effect before deploying them in a production environment.
31. **MaxClients** (set the maximum number of simultaneous connections allowed):
```
MaxClients 150
```
32. **ServerLimit** (set the maximum configured value for MaxClients):
```
ServerLimit 150
```
33. **StartServers**, **MinSpareServers**, and **MaxSpareServers** (configure the number of server processes to start and keep idle):
```
StartServers 5
MinSpareServers 5
MaxSpareServers 10
```
34. **MaxRequestsPerChild** (limit the number of requests served by a single child process before it's terminated and replaced):
```
MaxRequestsPerChild 1000
```
35. **AliasMatch** (define regex-based URL mapping to specific directories):
```
AliasMatch "^/user/(.+)/pics/(.+)" "/home/$1/pics/$2"
```
36. **RedirectMatch** (perform regex-based URL redirection):
```
RedirectMatch 301 ^/old-page/(.*)$ http://example.com/new-page/$1
```
37. **SetEnv** (set environment variables accessible by scripts or Apache modules):
```
SetEnv ENVIRONMENT production
```
38. **AddDefaultCharset** (specify the default character set for the server):
```
AddDefaultCharset UTF-8
```
39. **FileETag** (configure the generation of ETags for files):
```
FileETag MTime Size
```
40. **ProxyRequests** (enable or disable proxy requests):
```
ProxyRequests Off
```
41. **ProxyTimeout** (set the timeout for proxy requests):
```
ProxyTimeout 60
```
42. **ProxyVia** (add or remove the "Via" header in proxy requests):
```
ProxyVia On
```
43. **TraceEnable** (allow or deny the TRACE HTTP method):
```
TraceEnable Off
```
44. **SSLEngine**, **SSLCertificateFile**, and **SSLCertificateKeyFile** (configure SSL for secure connections):
```
SSLEngine On
SSLCertificateFile /path/to/certificate.pem
SSLCertificateKeyFile /path/to/private_key.pem
```
45. **Header always set Strict-Transport-Security** (enable HSTS to enforce secure connections):
```
Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains"
```
Remember that the specific directives you need will depend on your server's requirements and the features you want to enable. Always keep the Apache documentation handy to understand the purpose and usage of each directive accurately. Regularly review and update your server configuration to ensure security, performance, and compliance with best practices.
46. **AddOutputFilterByType** (apply output filters based on MIME types):
```
AddOutputFilterByType DEFLATE text/html text/plain text/xml
```
47. **SetOutputFilter** (set the output filters to be applied to a request):
```
SetOutputFilter DEFLATE
```
48. **ExpiresActive** and **ExpiresDefault** (configure browser caching using the Expires header):
```
ExpiresActive On
ExpiresDefault "access plus 1 month"
```
49. **Header set Cache-Control** (define the Cache-Control header for controlling caching behavior):
```
Header set Cache-Control "public, max-age=3600"
```
50. **ServerAlias** (set additional aliases for a virtual host):
```
ServerAlias www.example.com alias.example.com
```
51. **LogLevel** (set the level of verbosity for error logging):
```
LogLevel warn
```
52. **ProxyPass** and **ProxyPassReverse** (configure reverse proxy settings):
```
ProxyPass "/api" "http://backend-server/"
ProxyPassReverse "/api" "http://backend-server/"
```
53. **ProxyPreserveHost** (preserve the original host header in reverse proxy requests):
```
ProxyPreserveHost On
```
54. **ServerTokens** (set the level of detail in the Server response header):
```
ServerTokens Prod
```
55. **ServerSignature** (enable or disable server signature in error response pages):
```
ServerSignature Off
```
56. **LimitRequestBody** (set the maximum request body size in bytes):
```
LimitRequestBody 1048576
```
57. **LimitRequestLine** (set the maximum size of the HTTP request line in bytes):
```
LimitRequestLine 8190
```
58. **RewriteCond** (add conditions for URL rewriting using RewriteRule):
```
RewriteCond %{HTTP_HOST} ^www\.example\.com$
RewriteRule ^(.*)$ http://example.com$1 [R=301,L]
```
59. **RewriteBase** (set the base URL for URL rewriting):
```
RewriteBase /subdirectory/
```
60. **RemoteIPHeader** and **RemoteIPInternalProxy** (configure IP address reporting for the client's IP):
```
RemoteIPHeader X-Forwarded-For
RemoteIPInternalProxy 192.168.0.0/16
```
These are more directives that can be used to fine-tune and optimize your Apache Web Server configuration. Always test your configurations thoroughly and be cautious while implementing changes in a production environment. Keep the Apache documentation as your guide to understand the purpose and impact of each directive effectively.
61. **ProxyErrorOverride** (override backend server error pages with Apache's error pages for reverse proxy requests):
```
ProxyErrorOverride On
```
62. **ProxyBadHeader** (handle invalid headers in reverse proxy requests):
```
ProxyBadHeader Ignore
```
63. **RewriteMap** (define mapping for complex URL rewriting):
```
RewriteMap lc int:tolower
RewriteRule ^/products/(.*)$ /display_product.php?product=${lc:$1} [L]
```
64. **ProxyHTMLURLMap** (configure URL mapping for reverse proxy requests with mod_proxy_html):
```
ProxyHTMLURLMap http://backend-server/ /api/
```
65. **SetEnvIf** (set environment variables based on request headers or other variables):
```
SetEnvIf User-Agent "MSIE 8\.0" force-no-vary
```
66. **RequestHeader** (modify incoming request headers or add new ones):
```
RequestHeader set X-Custom-Header "Custom Value"
```
67. **FileETag** (configure how ETags are generated for files):
```
FileETag MTime Size
```
68. **FallbackResource** (specify a default resource when no other resource matches the request):
```
FallbackResource /index.php
```
69. **Header always set Content-Security-Policy** (define a Content Security Policy to mitigate cross-site scripting attacks):
```
Header always set Content-Security-Policy "default-src 'self'; img-src 'self' data:;"
```
70. **ServerAlias** (set additional aliases for a virtual host):
```
ServerAlias www.example.com alias.example.com
```
71. **SSLProtocol**, **SSLCipherSuite**, and **SSLHonorCipherOrder** (configure SSL/TLS protocols and ciphers):
```
SSLProtocol -all +TLSv1.2
SSLCipherSuite HIGH:MEDIUM:!aNULL:!MD5
SSLHonorCipherOrder on
```
72. **SSLCompression** (disable SSL/TLS compression to mitigate the CRIME attack):
```
SSLCompression Off
```
73. **SSLUseStapling** (enable OCSP stapling to improve SSL/TLS certificate validation):
```
SSLUseStapling On
```
74. **ProxyTimeout** (set the timeout for proxy requests):
```
ProxyTimeout 60
```
75. **ProxyPassMatch** (define regex-based reverse proxy settings):
```
ProxyPassMatch "^/(.*\.php(/.*)?)$" "fcgi://localhost:9000/var/www/$1"
```
These additional directives provide further customization options for your Apache Web Server configuration. Use them wisely and consider the security implications of each directive, especially if your server is exposed to the public internet. Always keep your server and software up to date to ensure a secure and high-performing web hosting environment. Additionally, regularly monitor server logs and test configurations to identify and address any issues that may arise.
76. **ProxyMaxForwards** (set the maximum number of proxy request forwarding):
```
ProxyMaxForwards 10
```
77. **SSLCertificateChainFile** (specify the certificate chain file for SSL/TLS):
```
SSLCertificateChainFile /path/to/certificate_chain_file.pem
```
78. **SSLVerifyClient** (enable client certificate authentication for SSL/TLS):
```
SSLVerifyClient require
```
79. **SSLVerifyDepth** (set the maximum depth of certificate verification for client authentication):
```
SSLVerifyDepth 2
```
80. **ErrorLogFormat** (customize the format of error log entries):
```
ErrorLogFormat "[%{cu}t] [%-m:%l] [pid %P:tid %T] %7F: %E: [client\ %a] %M% ,\ referer\ %{Referer}i\ ,\ %\ \ error\ %{ErrorDocument}o"
```
81. **TraceEnable** (allow or deny the TRACE HTTP method):
```
TraceEnable Off
```
82. **AddCharset** (specify the character set for specific file types):
```
AddCharset utf-8 .html .css .js
```
83. **LimitExcept** (restrict access to a set of HTTP methods for a directory):
```
<LimitExcept GET POST>
Require valid-user
</LimitExcept>
```
84. **RedirectPermanent** (perform permanent redirection using a 301 status code):
```
RedirectPermanent /old-page http://example.com/new-page
```
85. **BrowserMatch** (set environment variables based on user-agent):
```
BrowserMatch MSIE is_ie
```
86. **SetEnvIfExpr** (set environment variables based on expression matching):
```
SetEnvIfExpr "%{REQUEST_URI} == '/maintenance.html'" MAINTENANCE_MODE
```
87. **Timeout** (set the maximum time the server will wait for certain operations to complete):
```
Timeout 300
```
88. **Allow and Deny** (control access based on client IP addresses):
```
Deny from 192.168.1.100
Allow from all
```
89. **Satisfy** (set access control requirements for multiple authentication mechanisms):
```
Satisfy any
```
90. **ProxyErrorOverride** (override backend server error pages with Apache's error pages for reverse proxy requests):
```
ProxyErrorOverride On
```
These directives add more flexibility and control to your Apache Web Server configuration. Remember that each directive has specific use cases and potential impacts, so be sure to understand their purposes before applying them to your server. Regularly review your configuration and perform security audits to ensure that your web server remains secure, stable, and efficient. Additionally, always keep your server and software up-to-date to benefit from the latest security patches and performance improvements.
91. **LogLevel** (set the level of verbosity for error logging):
```
LogLevel warn
```
92. **RequestReadTimeout** (set the maximum time the server will wait for a request to be read):
```
RequestReadTimeout header=10 body=20
```
93. **ProxyErrorOverride** (override backend server error pages with Apache's error pages for reverse proxy requests):
```
ProxyErrorOverride On
```
94. **SSLSessionCache** (configure SSL/TLS session caching for performance improvement):
```
SSLSessionCache "shmcb:/path/to/cache_file(512000)"
SSLSessionCacheTimeout 300
```
95. **SSLSessionTickets** (enable or disable session ticket support for SSL/TLS session resumption):
```
SSLSessionTickets Off
```
96. **ProxyPassReverseCookieDomain** and **ProxyPassReverseCookiePath** (modify cookies in reverse proxy requests):
```
ProxyPassReverseCookieDomain backend-server.example.com frontend-server.example.com
ProxyPassReverseCookiePath / /app/
```
97. **RemoteIPHeader** and **RemoteIPInternalProxy** (configure IP address reporting for the client's IP):
```
RemoteIPHeader X-Forwarded-For
RemoteIPInternalProxy 192.168.0.0/16
```
98. **ProxyErrorOverride** (override backend server error pages with Apache's error pages for reverse proxy requests):
```
ProxyErrorOverride On
```
99. **FileETag** (configure how ETags are generated for files):
```
FileETag MTime Size
```
100. **SSLOptions** (configure SSL/TLS options):
```
SSLOptions +StrictRequire +StdEnvVars -ExportCertData
```
101. **SSLStrictSNIVHostCheck** (enable or disable strict SNI virtual host checking):
```
SSLStrictSNIVHostCheck On
```
102. **SSLOCSPEnable** (enable OCSP stapling for certificate validation):
```
SSLOCSPEnable On
```
103. **SSLOCSPResponseFile** (specify the file path containing OCSP response for stapling):
```
SSLOCSPResponseFile /path/to/ocsp_response_file.pem
```
104. **SSLSessionCacheTimeout** (set the timeout for SSL/TLS session cache entries):
```
SSLSessionCacheTimeout 300
```
105. **SSLCompression** (disable SSL/TLS compression to mitigate the CRIME attack):
```
SSLCompression Off
```
These directives provide additional control and optimization options for your Apache Web Server configuration. Make sure to review and understand the purpose of each directive to ensure the security and performance of your web server. Always test your configurations thoroughly and keep your server software up to date to stay protected against security vulnerabilities. Regularly monitor server logs and performance to identify any potential issues and address them promptly.
106. **ProxyReceiveBufferSize** (set the buffer size for receiving data from a backend server during reverse proxying):
```
ProxyReceiveBufferSize 1024
```
107. **LimitXMLRequestBody** (set the maximum request body size for XML requests):
```
LimitXMLRequestBody 1000000
```
108. **Header edit** (modify response headers using regular expressions):
```
Header edit Server Apache ApacheWebServer
```
109. **Filesmatch** (apply directives to files based on regex matching of the file path):
```
<FilesMatch "\.(html|css|js)$">
Header set Cache-Control "public, max-age=3600"
</FilesMatch>
```
110. **ProxyPassInterpolateEnv** (allow environment variables in ProxyPass arguments):
```
ProxyPassInterpolateEnv On
ProxyPass "/app" "http://${BACKEND_SERVER}:8080"
```
111. **RemoteIPTrustedProxy** (define a list of trusted proxy IP addresses for client IP determination):
```
RemoteIPTrustedProxy 192.168.1.100 192.168.1.101
```
112. **ProxyAddHeaders** (add or remove request headers in reverse proxy requests):
```
ProxyAddHeaders Off
```
113. **LogLevel** (set the level of verbosity for error logging):
```
LogLevel warn
```
114. **XSendFilePath** (enable the X-Sendfile header to serve files efficiently from the filesystem):
```
XSendFilePath /path/to/files
```
115. **ProxyPreserveHost** (preserve the original host header in reverse proxy requests):
```
ProxyPreserveHost On
```
116. **SSLStaplingCache** (configure the SSL/TLS stapling cache):
```
SSLStaplingCache "shmcb:/path/to/cache_file(128000)"
```
117. **SSLProxyCACertificateFile** (specify the CA certificate file for SSL/TLS proxying):
```
SSLProxyCACertificateFile /path/to/ca_certificate.pem
```
118. **SSLOCSPUseRequestNonce** (use a nonce in OCSP requests to improve security):
```
SSLOCSPUseRequestNonce On
```
119. **ServerTokens** (set the level of detail in the Server response header):
```
ServerTokens Prod
```
120. **Header always set Referrer-Policy** (control the behavior of the Referer header):
```
Header always set Referrer-Policy "strict-origin-when-cross-origin"
```
These directives offer advanced configurations and optimizations for your Apache Web Server. Use them wisely, and always test your changes thoroughly to ensure the desired outcome. Regularly monitor server performance and security to identify potential issues and address them promptly. Keeping your server and software up-to-date is crucial for maintaining a secure and high-performing web hosting environment.
121. **SSLSessionTicketKeyFile** (specify the file containing the session ticket encryption keys for SSL/TLS):
```
SSLSessionTicketKeyFile /path/to/session_ticket_key_file.key
```
122. **ProxyTimeout** (set the timeout for proxy requests):
```
ProxyTimeout 60
```
123. **Header always set X-Frame-Options** (set the X-Frame-Options header to prevent clickjacking attacks):
```
Header always set X-Frame-Options "SAMEORIGIN"
```
124. **Header always set X-XSS-Protection** (enable the XSS protection filter in browsers):
```
Header always set X-XSS-Protection "1; mode=block"
```
125. **Header always set X-Content-Type-Options** (prevent MIME type sniffing):
```
Header always set X-Content-Type-Options "nosniff"
```
126. **Header always set Content-Security-Policy** (define a Content Security Policy to mitigate various security risks):
```
Header always set Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline'; style-src 'self' 'unsafe-inline'; img-src 'self';"
```
127. **Header always set Strict-Transport-Security** (enable HSTS to enforce secure connections):
```
Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains"
```
128. **Header always set X-Permitted-Cross-Domain-Policies** (control Flash and Adobe Acrobat access to content):
```
Header always set X-Permitted-Cross-Domain-Policies "none"
```
129. **SSLInsecureRenegotiation** (allow insecure SSL/TLS renegotiation for compatibility with older clients):
```
SSLInsecureRenegotiation on
```
130. **SSLCompression** (disable SSL/TLS compression to mitigate the CRIME attack):
```
SSLCompression Off
```
131. **SSLHonorCipherOrder** (prefer server's cipher order over the client's):
```
SSLHonorCipherOrder on
```
132. **SSLCipherSuite** (specify the allowed SSL/TLS ciphers):
```
SSLCipherSuite EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH
```
133. **SSLOptions** (configure SSL/TLS options):
```
SSLOptions +StrictRequire +StdEnvVars -ExportCertData
```
134. **LimitRequestLine** (set the maximum size of the HTTP request line in bytes):
```
LimitRequestLine 8190
```
135. **LimitRequestBody** (set the maximum request body size in bytes):
```
LimitRequestBody 1048576
```
These directives focus on enhancing security by adding various HTTP security headers, configuring SSL/TLS options, and limiting the size of requests. Implementing proper security measures is crucial to protect your web server and users from potential threats. Always refer to official security guidelines and regularly update your server's security configurations to stay ahead of emerging threats. Additionally, consider enabling security modules such as mod_security to provide an additional layer of protection against web application attacks.
Here are more Apache Web Server configuration directives focusing on security, performance, and advanced features:
136. **SSLSessionTickets** (enable or disable session ticket support for SSL/TLS session resumption):
```
SSLSessionTickets Off
```
137. **SSLStaplingCache** (configure the SSL/TLS stapling cache):
```
SSLStaplingCache "shmcb:/path/to/cache_file(128000)"
```
138. **SSLUseStapling** (enable OCSP stapling to improve SSL/TLS certificate validation):
```
SSLUseStapling On
```
139. **SSLStrictSNIVHostCheck** (enable or disable strict SNI virtual host checking):
```
SSLStrictSNIVHostCheck On
```
140. **SSLOCSPUseRequestNonce** (use a nonce in OCSP requests to improve security):
```
SSLOCSPUseRequestNonce On
```
141. **ProxyTimeout** (set the timeout for proxy requests):
```
ProxyTimeout 60
```
142. **Header always set X-Frame-Options** (set the X-Frame-Options header to prevent clickjacking attacks):
```
Header always set X-Frame-Options "SAMEORIGIN"
```
143. **Header always set X-XSS-Protection** (enable the XSS protection filter in browsers):
```
Header always set X-XSS-Protection "1; mode=block"
```
144. **Header always set X-Content-Type-Options** (prevent MIME type sniffing):
```
Header always set X-Content-Type-Options "nosniff"
```
145. **Header always set Content-Security-Policy** (define a Content Security Policy to mitigate various security risks):
```
Header always set Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline'; style-src 'self' 'unsafe-inline'; img-src 'self';"
```
146. **Header always set Strict-Transport-Security** (enable HSTS to enforce secure connections):
```
Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains"
```
147. **Header always set X-Permitted-Cross-Domain-Policies** (control Flash and Adobe Acrobat access to content):
```
Header always set X-Permitted-Cross-Domain-Policies "none"
```
148. **SSLInsecureRenegotiation** (allow insecure SSL/TLS renegotiation for compatibility with older clients):
```
SSLInsecureRenegotiation on
```
149. **SSLCompression** (disable SSL/TLS compression to mitigate the CRIME attack):
```
SSLCompression Off
```
150. **SSLOptions** (configure SSL/TLS options):
```
SSLOptions +StrictRequire +StdEnvVars -ExportCertData
```
151. **LimitRequestLine** (set the maximum size of the HTTP request line in bytes):
```
LimitRequestLine 8190
```
152. **LimitRequestBody** (set the maximum request body size in bytes):
```
LimitRequestBody 1048576
```
153. **FileETag** (configure how ETags are generated for files):
```
FileETag MTime Size
```
154. **Header edit** (modify response headers using regular expressions):
```
Header edit Server Apache ApacheWebServer
```
155. **Filesmatch** (apply directives to files based on regex matching of the file path):
```
<FilesMatch "\.(html|css|js)$">
Header set Cache-Control "public, max-age=3600"
</FilesMatch>
```
156. **ProxyReceiveBufferSize** (set the buffer size for receiving data from a backend server during reverse proxying):
```
ProxyReceiveBufferSize 1024
```
157. **LimitXMLRequestBody** (set the maximum request body size for XML requests):
```
LimitXMLRequestBody 1000000
```
158. **ProxyPassInterpolateEnv** (allow environment variables in ProxyPass arguments):
```
ProxyPassInterpolateEnv On
ProxyPass "/app" "http://${BACKEND_SERVER}:8080"
```
159. **RemoteIPTrustedProxy** (define a list of trusted proxy IP addresses for client IP determination):
```
RemoteIPTrustedProxy 192.168.1.100 192.168.1.101
```
160. **ProxyAddHeaders** (add or remove request headers in reverse proxy requests):
```
ProxyAddHeaders Off
```
161. **Header always set Referrer-Policy** (control the behavior of the Referer header):
```
Header always set Referrer-Policy "strict-origin-when-cross-origin"
```
162. **Header always set X-Content-Security-Policy** (legacy version of Content Security Policy header):
```
Header always set X-Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline'; style-src 'self' 'unsafe-inline'; img-src 'self';"
```
163. **Header always set X-Download-Options** (prevent Internet Explorer from executing downloads):
```
Header always set X-Download-Options "noopen"
```
164. **Header always set X-Permitted-Cross-Domain-Policies** (control Adobe Flash and Acrobat access):
```
Header always set X-Permitted-Cross-Domain-Policies "none"
```
165. **Header always set X-Robots-Tag** (set the X-Robots-Tag header for search engine indexing):
```
Header always set X-Robots-Tag "noindex, nofollow"
```
166. **Header always set X-UA-Compatible** (specify the document mode for Internet Explorer):
```
Header always set X-UA-Compatible "IE=edge"
```
167. **Header always set X-Download-Options** (prevent Internet Explorer from executing downloads):
```
Header always set X-Download-Options "noopen"
```
168. **Header always set X-Content-Type-Options** (prevent MIME type sniffing):
```
Header always set X-Content-Type-Options "nosniff"
```
169. **Header always set X-Frame-Options** (set the X-Frame-Options header to prevent clickjacking attacks):
```
Header always set X-Frame-Options "SAMEORIGIN"
```
170. **Header always set X-XSS-Protection** (enable the XSS protection filter in browsers):
```
Header always set X-XSS-Protection "1; mode=block"
```
171. **Header always set Content-Security-Policy** (define a Content Security Policy to mitigate various security risks):
```
Header always set Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline'; style-src 'self' 'unsafe-inline'; img-src 'self';"
```
172. **Header always set Strict-Transport-Security** (enable HSTS to enforce secure connections):
```
Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains"
```
173. **Header always set X-Permitted-Cross-Domain-Policies** (control Flash and Adobe Acrobat access to content):
```
Header always set X-Permitted-Cross-Domain-Policies "none"
```
174. **Header always set Feature-Policy** (control which features can be used on the page):
```
Header always set Feature-Policy "geolocation 'self'; microphone 'none'; camera 'none'"
```
175. **Header always set Referrer-Policy** (control the behavior of the Referer header):
```
Header always set Referrer-Policy "strict-origin-when-cross-origin"
```
These directives continue to focus on enhancing security and performance by setting various HTTP security headers, configuring SSL/TLS options, and controlling the behavior of your web server. Always ensure that you understand the implications of each directive and test your configurations thoroughly to achieve the desired outcome. Regularly review and update your server's configurations to stay up-to-date with the latest best practices and security guidelines. Additionally, consider implementing additional security measures, such as web application firewalls, to further protect your web applications from potential threats.