nginx
| Basic HTTP server features Other HTTP server features Mail proxy server features TCP/UDP proxy server features Architecture and scalability Tested OS and platforms |
nginx ("engine x") is an HTTP web server, reverse proxy, content cache, load balancer, TCP/UDP proxy server, and mail proxy server. Originally written by Igor Sysoev and distributed under the 2-clause BSD License.
Known for flexibility and high performance with low resource utilization, nginx is:
- the world's most popular web server [Netcraft];
- consistently one of the most popular Docker images [DataDog];
- powering multiple Ingress Controllers for Kubernetes, including our own.
Enterprise distributions, commercial support and training are available from F5, Inc.
Basic HTTP server features
- Serving static and index files, autoindexing; open file descriptor cache;
- Accelerated reverse proxying with caching; load balancing and fault tolerance;
- Accelerated support with caching of FastCGI, uwsgi, SCGI, and memcached servers; load balancing and fault tolerance;
- Modular architecture. Filters include gzipping, byte ranges, chunked responses, XSLT, SSI, and image transformation filter. Multiple SSI inclusions within a single page can be processed in parallel if they are handled by proxied or FastCGI/uwsgi/SCGI servers;
- SSL and TLS SNI support;
- Support for HTTP/2 with weighted and dependency-based prioritization;
- Support for HTTP/3.
Other HTTP server features
- Name-based and IP-based virtual servers;
- Keep-alive and pipelined connections support;
- Access log formats, buffered log writing, fast log rotation, and syslog logging;
- 3xx-5xx error codes redirection;
- The rewrite module: URI changing using regular expressions;
- Executing different functions depending on the client address;
- Access control based on client IP address, by password (HTTP Basic authentication) and by the result of subrequest;
- Validation of HTTP referer;
- The PUT, DELETE, MKCOL, COPY, and MOVE methods;
- FLV and MP4 streaming;
- Response rate limiting;
- Limiting the number of simultaneous connections or requests coming from one address;
- IP-based geolocation;
- A/B testing;
- Request mirroring;
- Embedded Perl;
- njs scripting language.
Mail proxy server features
- User redirection to IMAP or POP3 server using an external HTTP authentication server;
- User authentication using an external HTTP authentication server and connection redirection to an internal SMTP server;
- Authentication methods:
- SSL support;
- STARTTLS and STLS support.
TCP/UDP proxy server features
- Generic proxying of TCP and UDP;
- SSL and TLS SNI support for TCP;
- Load balancing and fault tolerance;
- Access control based on client address;
- Executing different functions depending on the client address;
- Limiting the number of simultaneous connections coming from one address;
- Access log formats, buffered log writing, fast log rotation, and syslog logging;
- IP-based geolocation;
- A/B testing;
- njs scripting language.
Architecture and scalability
- One master and several worker processes; worker processes run under an unprivileged user;
- Flexible configuration;
- Reconfiguration and upgrade of an executable without interruption of the client servicing;
- Support for kqueue (FreeBSD 4.1+), epoll (Linux 2.6+), /dev/poll (Solaris 7 11/99+), event ports (Solaris 10), select, and poll;
- The support of the various kqueue features including EV_CLEAR, EV_DISABLE (to temporarily disable events), NOTE_LOWAT, EV_EOF, number of available data, error codes;
- The support of various epoll features including EPOLLRDHUP (Linux 2.6.17+, glibc 2.8+) and EPOLLEXCLUSIVE (Linux 4.5+, glibc 2.24+);
- sendfile (FreeBSD 3.1+, Linux 2.2+, macOS 10.5+), sendfile64 (Linux 2.4.21+), and sendfilev (Solaris 8 7/01+) support;
- File AIO (FreeBSD 4.3+, Linux 2.6.22+);
- DIRECTIO (FreeBSD 4.4+, Linux 2.4+, Solaris 2.6+, macOS);
- Accept-filters (FreeBSD 4.1+, NetBSD 5.0+) and TCP_DEFER_ACCEPT (Linux 2.4+) support;
- 10,000 inactive HTTP keep-alive connections take about 2.5M memory;
- Data copy operations are kept to a minimum.
Tested OS and platforms
- FreeBSD 3 — 12 / i386; FreeBSD 5 — 12 / amd64; FreeBSD 11 / ppc; FreeBSD 12 / ppc64;
- Linux 2.2 — 4 / i386; Linux 2.6 — 5 / amd64; Linux 3 — 4 / armv6l, armv7l, aarch64, ppc64le; Linux 4 — 5 / s390x;
- Solaris 9 / i386, sun4u; Solaris 10 / i386, amd64, sun4v; Solaris 11 / x86;
- AIX 7.1 / powerpc;
- HP-UX 11.31 / ia64;
- macOS / ppc, i386, x86_64;
- Windows XP, Windows Server 2003, Windows 7, Windows 10, Windows 11.