Comment 1 for bug 1531150

A workaround is two-fold:

a) add the proxy lines to /etc/default/landscape-client;
export http_proxy=http://<your-proxy>/
export https_proxy=http://<your-proxy>/
export no_proxy=localhost,127.0.0.1,<others-if-needed>

Obviously replace <your-proxy> with your proxy IP/hostname, and port if needed.

That takes care of the hash-id download problem.

b) for the apt-get update suid root wrapper, create this file /etc/apt/apt.conf.d/50-proxy:
Acquire::http::Proxy "http://<your-proxy>/";
Acquire::https::Proxy "http://<your-proxy>/";

Again, replace <your-proxy> as before.