Need to set a HTTP proxy within a Debian system ?
Assuming your proxy server is on 192.168.0.1 and listening on port 3128, then the below may help …
( If you need authentication you can use username:password@ like you would in an old style web browser – e.g. http://username:password@192.168.0.1:3128. )
/etc/profile.d/proxy.sh
Add /etc/profile.d/proxy.sh containing
export http_proxy=http://192.168.0.1:3128
/etc/apt/apt.conf.d/99HttpProxy
Add /etc/apt/apt.conf.d/99HttpProxy containing
Acquire::http::Proxy "http://192.168.0.1:3128";
/etc/wgetrc
Edit /etc/wgetrc and add
http_proxy = http://192.168.0.1:3128
(some system commands rely on wget, and may not otherwise use an environment variable, e.g. debootstrap; the http_proxy setting should be present by default but commented out).
(This is all, in a round about way, relayed to the http proxy security vulnerability announced in July 2016 – see httpoxy.org for more info)