keyid=lange_keyid_die_apt_anmeckert ; 
gpg --keyserver subkeys.pgp.net --recv-key $keyid ; 
gpg --fingerprint $keyid ; 

FINGERPRINT KONTROLLIEREN 
gpg --armor --export $keyid | apt-key add - 

Überprüft unbedingt den Fingerprint des Servers !!

Das eigentliche Tool für den Key-Import ist apt-key. (man apt-key für mehr Infos)

Die meisten Server mit alternativen Debian Paketen haben auch eine Anleitung online. Zum Beispiel http://www.debian-multimedia.org/ .

--

Issue

When updating the Debian based system, it may happens that the apt-get displays an error message like:

W: GPG error: ftp://ftp.debian.org/ testing Release:     
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 010908312D230C5F    

W: There is no public key available for the following key IDs:    
010908312D230C5F

This is a new feature of the apt-get system that guarantee the authenticity of servers for updating Debian.

Solution

Simply type the following commands, taking care to replace the number of the key that displayed in the error message:

gpg --keyserver pgpkeys.mit.edu --recv-key  010908312D230C5F    
gpg -a --export 010908312D230C5F | sudo apt-key add -

http://repogen.simplylinux.ch/

apt-get update && apt-get upgrade

apt-get autoremove

do-release-upgrade

 /etc/apt/apt.conf

Acquire::http::proxy "http://172.16.1.8:8080/";