Facebook is the social network that governments have blocked for the longest and the most often. China cut it off in 2009 after unrest in Xinjiang and never reconnected it. Iran blocked it the same year. Russia blocked it in March 2022. Uganda switched it off before its 2021 election and left it off. Myanmar's military blocked it after the 2021 coup. Bangladesh, Pakistan and Sri Lanka have each cut it for days or weeks during protests, and Vietnam has slowed it down at sensitive moments.
The method is standard: the carriers drop Meta's address ranges and stop facebook.com and its content domains resolving, and in the countries with deep packet inspection the encrypted connection is recognised and reset. Messenger usually goes down with it, since it runs on the same infrastructure.
A VPN restores Facebook by moving your traffic to a server in a country where it is reachable, inside a tunnel the local network cannot inspect. GhostShield's WireGuard tunnel carries the feed, Marketplace, groups, video and Messenger calls at full speed.
Facebook does watch for logins from unfamiliar places. The first time you connect through a server in another country you may be asked to confirm it is you, by code or by recognising friends in photos. Using the same server location each time keeps those checks rare, and connecting through your own country when you can avoids them almost entirely.