Debian 8 jessie

/etc/apt/apt.conf

Acquire::Check-Valid-Until "false";

/etc/apt/sources.list

deb http://cdn-fastly.deb.debian.org/debian/ jessie main
deb-src http://cdn-fastly.deb.debian.org/debian/ jessie main
 
deb http://security.debian.org/ jessie/updates main
deb-src http://security.debian.org/ jessie/updates main
 
deb http://archive.debian.org/debian jessie-backports main
deb-src http://archive.debian.org/debian jessie-backports main