On Debian-based distros there are several tools. squid-deb-proxy can do most of this - it fetches and locally caches lists and packages. Clients install squid-

On Debian-based distros there are several tools. squid-deb-proxy can do most of this - it fetches and locally caches lists and packages. Clients install squid-deb-proxy-client which uses multicast-DNS to discover the local proxy. Packages are fetched and cached by the proxy first time they're requested and thereafter served locally (subject to lifetime/space etc. squid configuration). There are ways to pre-populate the cache but you're always going to have situations where package updates have to pull from remote archives. apt-mirror is designed for a similar purpose. It allows creating a sub-set or entire mirror of one or more upstream archives. Clients can then be pointed at the local mirror which could be on the same host or LAN. Generally, 'packages' on github will be source-code only so you'd need a quite complex build server, or at least per-package specific links in your local cache rules for pre-built binaries.