ci.guix.gnu.org and bordeaux.guix.gnu.org
are both front-ends to official build farms that build packages from Guix
continuously for some architectures, and make them available as
substitutes. These are the default source of substitutes; which can be
overridden by passing the --substitute-urls option either to
guix-daemon (see guix-daemon
--substitute-urls) or to client tools such as guix package
(see client --substitute-urls option).
Las URLs de sustituciones pueden ser tanto HTTP como HTTPS. Se recomienda HTTPS porque las comunicaciones están cifradas; de modo contrario, usar HTTP hace visibles todas las comunicaciones para alguien que las intercepte, quien puede usar la información obtenida para determinar, por ejemplo, si su sistema tiene vulnerabilidades de seguridad sin parchear.
Substitutes from the official build farms are enabled by default when using Guix System (see Distribución GNU). However, they are disabled by default when using Guix on a foreign distribution, unless you have explicitly enabled them via one of the recommended installation steps (see Instalación). The following paragraphs describe how to enable or disable substitutes for the official build farm; the same procedure can also be used to enable substitutes for any other substitute server.