For what it's worth:
I setup a test VM with Vultr (Debian 7 x86) and noticed constant remote server connections from port 80.
I proceeded to block the connections with iptables.
Started having issues updating the system and it turns out that all/most of these IPs are Debian update servers.
128.61.240.73
128.61.240.89
128.61.240.73
108.59.6.136
205.234.175.175
128.31.0.36
149.20.20.6
195.234.148.10
Somehow these Debian servers are connecting constantly to my IP.
By the way, I installed from original Debian ISOs and DON'T have unattended-upgrades.