NAME

       cdist-type__haproxy_dualstack - Proxy services from a dual-stack server

DESCRIPTION

       This  (singleton)  type  installs  and  configures  haproxy to act as a dual-stack proxy for single-stack
       services.

       This can be useful to add IPv4 support to IPv6-only services while only using  one  IPv4  for  many  such
       services.

       By default this type uses the plain TCP proxy mode, which means that there is no need for TLS termination
       on this host when SNI is supported.  This also means that proxied services will not receive the  client's
       IP address, but will see the proxy's IP address instead (that of $__target_host).

       This  can  be  solved by using the PROXY protocol, but do take into account that, e.g. nginx cannot serve
       both regular HTTP(S) and PROXY protocols on the same port, so you will need to use other ports for that.

       As a recommendation in this type: use TCP ports 8080 and 591 respectively to serve HTTP and  HTTPS  using
       the PROXY protocol.

       See the EXAMPLES for more details.

OPTIONAL PARAMETERS

       v4proxy
              Proxy  incoming IPv4 connections to the equivalent IPv6 endpoint.  In its simplest use, it must be
              a NAME with an AAAA DNS entry, which is the IP address actually providing  the  proxied  services.
              The  full  format  of  this argument is: [proxy:]NAME[[:PROTOCOL_1=PORT_1]...[:PROTOCOL_N=PORT_N]]
              Where starting with proxy: determines that the PROXY protocol must be used and each :PROTOCOL=PORT
              (e.g. :http=8080 or :https=591) is a PORT override for the given PROTOCOL (see --protocol), if not
              present the PROTOCOL's default port will be used.

       v6proxy
              Proxy incoming IPv6 connections to the equivalent IPv4 endpoint.  In its simplest use, it must  be
              a  NAME with an A DNS entry, which is the IP address actually providing the proxied services.  See
              --v4proxy for more options and details.

       protocol
              Can be passed multiple times or as a  space-separated  list  of  protocols.   Currently  supported
              protocols are: http, https, imaps, smtps.  This defaults to: http https imaps smtps.

EXAMPLES

          # Proxy the IPv6-only services so IPv4-only clients can access them
          # This uses HAProxy's TCP mode for http, https, imaps and smtps
          __haproxy_dualstack \
              --v4proxy ipv6.chat \
              --v4proxy matrix.ungleich.ch

          # Proxy the IPv6-only HTTP(S) services so IPv4-only clients can access them
          # Note this means that the backend IPv6-only server will only see
          # the IPv6 address of the haproxy host managed by cdist, which can be
          # troublesome if this information is relevant for analytics/security/...
          # See the PROXY example below
          __haproxy_dualstack \
              --protocol http --protocol https \
              --v4proxy ipv6.chat \
              --v4proxy matrix.ungleich.ch

          # Use the PROXY protocol to proxy the IPv6-only HTTP(S) services enabling
          # IPv4-only clients to access them while maintaining the client's IP address
          __haproxy_dualstack \
              --protocol http --protocol https \
              --v4proxy proxy:ipv6.chat:http=8080:https=591 \
              --v4proxy proxy:matrix.ungleich.ch:http=8080:https=591
          # Note however that the PROXY protocol is not compatible with regular
          # HTTP(S) protocols, so your nginx will have to listen on different ports
          # with the PROXY settings.
          # Note that you will need to restrict access to the 8080 port to prevent
          # Client IP spoofing.
          # This can be something like:
          # server {
          #     # listen for regular HTTP connections
          #     listen [::]:80 default_server;
          #     listen 80 default_server;
          #     # listen for PROXY HTTP connections
          #     listen [::]:8080 proxy_protocol;
          #     # Accept the Client's IP from the PROXY protocol
          #     real_ip_header proxy_protocol;
          # }

SEE ALSO

       • https://www.haproxy.com/blog/enhanced-ssl-load-balancing-with-server-name-indication-sni-tls-extension/

       • https://www.haproxy.com/blog/haproxy/proxy-protocol/

       • https://docs.nginx.com/nginx/admin-guide/load-balancer/using-proxy-protocol/

AUTHORS

       ungleich <foss--@--ungleich.ch> Evilham <cvs--@--evilham.com>

COPYING

       Copyright  (C)  2021  ungleich glarus ag. You can redistribute it and/or modify it under the terms of the
       GNU General Public License as published by the Free Software Foundation, either version 3 of the License,
       or (at your option) any later version.

COPYRIGHT

       ungleich GmbH 2021