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<article name="Support for QUIC and HTTP/3"
         link="/en/docs/quic.html"
         lang="en"
         rev="2">

<section>

<para>
Support for
<link url="https://datatracker.ietf.org/doc/html/rfc9000">QUIC</link>
and
<link url="https://datatracker.ietf.org/doc/html/rfc9114">HTTP/3</link>
protocols is available since 1.25.0.
Also, since 1.25.0, the QUIC and HTTP/3 support is available in
Linux <link doc="../linux_packages.xml">binary packages</link>.
</para>

<para>
<note>
The QUIC and HTTP/3 support is experimental, caveat emptor applies.
</note>
</para>

</section>


<section id="building" name="Building from sources">

<para>
The build is configured using the <command>configure</command> command.
Please refer to <link doc="configure.xml"/> for details.
</para>

<para>
When configuring nginx, it is possible to enable QUIC and HTTP/3 using the
<link doc="configure.xml" id="http_v3_module"><literal>--with-http_v3_module</literal></link>
configuration parameter.
</para>

<para>
An SSL library that provides QUIC support is recommended to build nginx, such as
<link url="https://boringssl.googlesource.com/boringssl">BoringSSL</link>,
<link url="https://www.libressl.org">LibreSSL</link>, or
<link url="https://github.com/quictls/openssl">QuicTLS</link>.
Otherwise, the <link url="https://openssl.org">OpenSSL</link>
compatibility layer will be used that does not support
<link doc="http/ngx_http_ssl_module.xml" id="ssl_early_data">early data</link>.
</para>

<para>
Use the following command to configure nginx with
<link url="https://boringssl.googlesource.com/boringssl">BoringSSL</link>:
<programlisting>
./configure
    --with-debug
    --with-http_v3_module
    --with-cc-opt="-I../boringssl/include"
    --with-ld-opt="-L../boringssl/build/ssl
                   -L../boringssl/build/crypto"
</programlisting>
</para>

<para>
Alternatively, nginx can be configured with
<link url="https://github.com/quictls/openssl">QuicTLS</link>:
<programlisting>
./configure
    --with-debug
    --with-http_v3_module
    --with-cc-opt="-I../quictls/build/include"
    --with-ld-opt="-L../quictls/build/lib"
</programlisting>
</para>

<para>
Alternatively, nginx can be configured with a modern version of
<link url="https://www.libressl.org">LibreSSL</link>:
<programlisting>
./configure
    --with-debug
    --with-http_v3_module
    --with-cc-opt="-I../libressl/build/include"
    --with-ld-opt="-L../libressl/build/lib"
</programlisting>
</para>

<para>
After configuration,
nginx is compiled and installed using <command>make</command>.
</para>

</section>


<section id="configuration" name="Configuration">

<para>
The <link doc="http/ngx_http_core_module.xml" id="listen"/> directive in
<link doc="http/ngx_http_core_module.xml">ngx_http_core_module</link>
module got a new parameter
<link doc="http/ngx_http_core_module.xml" id="quic">quic</link>
which enables HTTP/3 over QUIC on the specified port.
</para>

<para>
Along with the <literal>quic</literal> parameter
it is also possible to specify the
<link doc="http/ngx_http_core_module.xml" id="reuseport">reuseport</link>
parameter to make it work properly with multiple workers.
</para>

<para>
For the list of directives, see
<link doc="http/ngx_http_v3_module.xml">ngx_http_v3_module</link>.
</para>

<para>
To <link doc="http/ngx_http_v3_module.xml" id="quic_retry">enable</link>
address validation:
<programlisting>
quic_retry on;
</programlisting>

To <link doc="http/ngx_http_ssl_module.xml" id="ssl_early_data">enable</link>
0-RTT:
<programlisting>
ssl_early_data on;
</programlisting>

To <link doc="http/ngx_http_v3_module.xml" id="quic_gso">enable</link>
GSO (Generic Segmentation Offloading):
<programlisting>
quic_gso on;
</programlisting>

To <link doc="http/ngx_http_v3_module.xml" id="quic_host_key">set</link>
host key for various tokens:
<programlisting>
quic_host_key &lt;filename&gt;;
</programlisting>
</para>

<para>
QUIC requires TLSv1.3 protocol version which is enabled by default
in the <link doc="http/ngx_http_ssl_module.xml" id="ssl_protocols"/> directive.
</para>

<para>
By default,
<link url="http://vger.kernel.org/lpc_net2018_talks/willemdebruijn-lpc2018-udpgso-paper-DRAFT-1.pdf">GSO Linux-specific optimization</link>
is disabled.
Enable it in case a corresponding network interface is configured
to support GSO.
</para>

</section>


<section id="example" name="Example Configuration">

<para>
<example>
http {
    log_format quic '$remote_addr - $remote_user [$time_local] '
                    '"$request" $status $body_bytes_sent '
                    '"$http_referer" "$http_user_agent" "$http3"';

    access_log logs/access.log quic;

    server {
        # for better compatibility it's recommended
        # to use the same port for quic and https
        listen 8443 quic reuseport;
        listen 8443 ssl;

        ssl_certificate     certs/example.com.crt;
        ssl_certificate_key certs/example.com.key;

        location / {
            # required for browsers to direct them to quic port
            add_header Alt-Svc 'h3=":8443"; ma=86400';
        }
    }
}
</example>
</para>

</section>


<section id="troubleshooting " name="Troubleshooting">

<para>
Tips that may help to identify problems:
<list type="bullet">

<listitem>
Ensure nginx is built with the proper SSL library.
</listitem>

<listitem>
Ensure nginx is using the proper SSL library in runtime
(the <literal>nginx -V</literal> shows what it is currently used).
</listitem>

<listitem>
Ensure a client is actually sending requests over QUIC.
It is recommended to start with a simple console client such as
<link url="https://nghttp2.org/ngtcp2">ngtcp2</link>
to ensure the server is configured properly before trying
with real browsers that may be quite picky with certificates.
</listitem>

<listitem>
Build nginx with <link doc="debugging_log.xml">debug support</link>
and check the debug log.
It should contain all details about the connection and why it failed.
All related messages contain the “<literal>quic</literal>” prefix
and can be easily filtered out.
</listitem>

<listitem>
For a deeper investigation, additional debugging can be enabled
using the following macros:
<literal>NGX_QUIC_DEBUG_PACKETS</literal>,
<literal>NGX_QUIC_DEBUG_FRAMES</literal>,
<literal>NGX_QUIC_DEBUG_ALLOC</literal>,
<literal>NGX_QUIC_DEBUG_CRYPTO</literal>.

<para>
<programlisting>
./configure
    --with-http_v3_module
    --with-debug
    --with-cc-opt="-DNGX_QUIC_DEBUG_PACKETS -DNGX_QUIC_DEBUG_CRYPTO"
</programlisting>
</para>
</listitem>

</list>
</para>

</section>

</article>