1. What is Nginx?

Nginx is a high-performance, open-source web server and reverse proxy server known for its speed, scalability, and efficient handling of concurrent connections.

2. How does Nginx differ from Apache?

Nginx is designed to handle a large number of concurrent connections with low memory usage, making it more suitable for high-traffic websites. Apache, while feature-rich, may consume more resources.

3. What is the role of Nginx as a reverse proxy?

As a reverse proxy, Nginx forwards client requests to backend servers, acting as an intermediary. It can also perform load balancing and SSL termination.

4. Can Nginx handle SSL/TLS termination?

Yes, Nginx can terminate SSL/TLS connections, offloading the decryption process and improving performance.

5. How can Nginx improve website performance?

Nginx improves performance by efficiently handling static content, serving as a reverse proxy, and utilizing features like caching and load balancing.

6. What is the Nginx configuration file and where is it located?

The main Nginx configuration file is usually named nginx.conf and is typically located in the /etc/nginx/ directory.

7. How can you test the Nginx configuration for syntax errors?

You can test the Nginx configuration for syntax errors using the command: nginx -t.

8. What is the purpose of the Nginx worker process?

The Nginx worker process handles incoming connections and processes requests. It can be configured to spawn multiple worker processes to handle concurrent connections efficiently.

9. How does Nginx handle static content?

Nginx efficiently serves static content by directly sending files to clients without involving the application server, reducing resource usage.

10. What is the location directive in Nginx configuration?

The location directive is used to define how Nginx should process requests that match a specific URI pattern. It allows for customization of behavior based on URL paths.

11. Can Nginx be used as a load balancer?

Yes, Nginx can be used as a load balancer to distribute incoming traffic across multiple backend servers, improving scalability and availability.

12. How does Nginx handle dynamic content?

Nginx can pass dynamic content requests to backend application servers using fastCGI, proxying requests to application server processes like those running PHP, Python, or Node.js.

13. What is the purpose of the upstream directive in Nginx?

The upstream directive defines a group of servers that can be used as backend servers. It is often used in the context of load balancing.

14. How does Nginx handle WebSocket connections?

Nginx supports WebSocket connections and can act as a WebSocket proxy, allowing for efficient communication between clients and WebSocket-enabled backend servers.

15. Can Nginx be used to serve as a caching proxy?

Yes, Nginx can be configured as a caching proxy to store and serve cached copies of static content, reducing the load on backend servers.

16. What is the difference between proxy_pass and fastcgi_pass in Nginx?

proxy_pass is used for proxying HTTP requests, while fastcgi_pass is used for passing requests to a FastCGI server, typically used for processing dynamic content.

17. How can you enable gzip compression in Nginx?

Gzip compression can be enabled in Nginx by adding the gzip on; directive in the configuration file.

18. What is the purpose of the Nginx rewrite directive?

The rewrite directive in Nginx is used to modify request URIs or perform URL redirections based on specified conditions.

19. How can you restrict access to a specific location in Nginx?

Access can be restricted in Nginx using the location directive combined with the allow and deny directives or using HTTP authentication.

20. Can Nginx serve as a mail proxy?

Yes, Nginx can act as a mail proxy to forward and load balance email traffic to backend mail servers.

21. How does Nginx handle SSL certificates?

Nginx can be configured to use SSL certificates for secure connections. SSL certificates are specified in the configuration using directives like ssl_certificate and ssl_certificate_key.

22. What is the purpose of the Nginx try_files directive?

The try_files directive in Nginx is used to define a series of files or URIs to attempt to serve in the specified order until a match is found.

23. Can Nginx be used for HTTP/2 support?

Yes, Nginx supports HTTP/2, providing improved performance, multiplexing, and header compression for modern web applications.

24. How can you set up virtual hosts in Nginx?

Virtual hosts, or server blocks in Nginx, can be set up by defining multiple server blocks in the configuration file, each with its own server_name.

25. What is the Nginx root directive used for?

The root directive in Nginx sets the root directory for requests, specifying the base directory from which to serve files.

26. Can Nginx be configured to log access and error information?

Yes, Nginx can be configured to log access and error information. Access logs record details about requests, while error logs capture information about server errors.

27. How can you perform a graceful restart of Nginx?

A graceful restart of Nginx can be performed using the command: nginx -s reload. This allows for configuration changes without interrupting active connections.

28. What is the purpose of the Nginx include directive?

The include directive is used to include additional configuration files within the main Nginx configuration file, aiding in modular configuration management.

29. How can you deny access to specific IP addresses in Nginx?

Access can be denied to specific IP addresses in Nginx using the deny directive within a location block or by using the allow and deny directives in conjunction.

30. What is the difference between listen and server_name directives in Nginx?

The listen directive specifies the IP address and port on which Nginx should listen, while server_name specifies the domain name for the server block.

31. Can Nginx be configured to handle SSL termination and pass unencrypted traffic to backend servers?

Yes, Nginx can be configured to handle SSL termination, decrypting SSL traffic, and forwarding unencrypted traffic to backend servers.

32. What is the purpose of the Nginx resolver directive?

The resolver directive in Nginx specifies the DNS server(s) used for domain name resolution when proxying requests or performing upstream server checks.

33. How can you limit the number of connections per IP in Nginx?

The limit_conn and limit_conn_zone directives in Nginx can be used to limit the number of connections from a single IP address.

34. Can Nginx be used for URL redirections?

Yes, Nginx can be configured for URL redirections using the rewrite directive or by specifying a return directive with the appropriate HTTP status code.

35. How does Nginx handle high traffic and concurrent connections?

Nginx is designed to handle high traffic and concurrent connections efficiently by using an event-driven, asynchronous architecture.

36. Can Nginx be used in a microservices architecture?

Yes, Nginx can be used in a microservices architecture to route and load balance requests between different microservices.

37. What is the Nginx autoindex directive used for?

The autoindex directive controls directory listing, allowing or disallowing the display of the contents of a directory when no index file is present.

38. How can you block specific user-agents in Nginx?

Specific user-agents can be blocked in Nginx using the if directive and checking the $http_user_agent variable.

39. What is the purpose of the Nginx map directive?

The map directive in Nginx allows for the creation of key-value mappings that can be used in conditional statements.

40. Can Nginx be used to serve static files efficiently?

Yes, Nginx excels at serving static files efficiently due to its event-driven architecture and the ability to handle a large number of concurrent connections.

41. What is the purpose of the Nginx proxy_set_header directive?

The proxy_set_header directive in Nginx is used to set additional headers when forwarding requests to backend servers, allowing for customization and control.

42. How does Nginx handle connection timeouts?

Nginx allows configuration of connection timeouts using directives like client_body_timeout, client_header_timeout, send_timeout, and keepalive_timeout.

43. Can Nginx be configured for load balancing with session persistence?

Yes, Nginx supports session persistence in load balancing scenarios through the use of sticky sessions or session persistence mechanisms.

44. What is the purpose of the Nginx fastcgi_param directive?

The fastcgi_param directive in Nginx is used to pass parameters to FastCGI backend servers when processing dynamic content.

45. How can you enable basic authentication in Nginx?

Basic authentication can be enabled in Nginx using the auth_basic and auth_basic_user_file directives to specify a password file.

46. What is the role of the Nginx location ~ directive?

The location ~ directive in Nginx is used for case-sensitive regular expression matching, allowing for more complex URI pattern matching.

47. Can Nginx be used as a WebSocket proxy for real-time applications?

Yes, Nginx can be configured as a WebSocket proxy to handle and forward WebSocket connections for real-time applications.

48. How does Nginx handle security vulnerabilities and updates?

Nginx provides regular updates to address security vulnerabilities. Users are encouraged to stay informed about updates and apply them promptly.

49. Can Nginx be configured to serve as a content delivery network (CDN)?

Yes, Nginx can be configured as a CDN by using features like caching, load balancing, and efficient handling of static content.

50. What is the purpose of the Nginx resolver_timeout directive?

The resolver_timeout directive in Nginx sets the maximum time allowed for DNS resolution, controlling the timeout period for DNS queries.