I’ve been setting up a number of apt-cacher instances on different networks I run Ubuntu boxes on. This is a well documented process. I’m posting the key steps if only for my own reference later.
1. apt-get install apt-cacher
2. Edit /etc/default/apt-cacher add AUTOSTART=1.
3. Edit /etc/apt-cacher/apt-cacher.conf and make sure the allowed_hosts line is explicitly as intended.
4. Open client (and local server’s) /etc/apt/sources.list and str repl %s/http:\/\//http:\/\/SERVERHOSTNAME:3142\/apt-cacher\//g
Default port is 3142