# Iran: shutdowns, protocol whitelisting and your configs

HTML: https://v2rc.app/learn/iran/ · Last reviewed: 2026-11-06

What research shows about Iran's 2025 and 2026 shutdowns, why only ports 53, 80 and 443 worked, and how to prepare your configs.

Status as of 2026-11-06. Blocking changes from week to week and differs by network. Read this as background, not as a guarantee, and check the sources at the end.

Iran has moved from blocking individual websites to controlling which protocols may leave the country at all. This article summarises what published measurements show, what is only claimed, and what follows in practice. If you are short of time, read the last point under “What follows in practice”: no tool defeats a complete shutdown.

## What the research shows

- **Mid-2025.** A measurement paper, [Iran's Stealth Internet Blackout](https://arxiv.org/abs/2507.14183), describes a shutdown that kept Iran in the global routing table while isolating users through deep packet inspection, aggressive throttling and selective protocol blocking. The measurements found DNS poisoning, HTTP injection, TLS interception and protocol whitelisting, traced to a centralised border gateway. In its tests, DNS over UDP (port 53), HTTP (80) and HTTPS (443) from Iranian networks to outside servers generally went through, while OpenVPN on UDP 1194 and generic TCP or UDP on other ports (for example 22, 1883 or custom ports) were dropped without any reply.
- **January 2026.** A second paper, [Iran's January 2026 Internet Shutdown](https://arxiv.org/abs/2603.28753), reconstructs the shutdown during the protests, the "new normal" that followed, and how circumvention tools fared, using public data from monitoring initiatives plus some private measurements. It cites earlier measurements that found enforcement differing between networks, with some applying near-complete censorship of DNS, HTTP and UDP and others almost none, and cautions that this does not necessarily describe the shutdown of 8 January 2026.
- **Automated address blocking.** The circumvention-tool developer Amnezia reports that blocking of VPN server addresses, once manual, became automated after the January shutdown. This comes from a tool vendor, not from independent measurement.
- **Since late February 2026.** An opinion piece in Iran International states that a nationwide shutdown has kept Iranians at roughly 1% connectivity since 28 February 2026. We treat that as a claim from one source. Check a live monitor for the current state.

## What follows in practice

1. **Use port 443 with a setup that looks like HTTPS.** In the 2025 measurements, other ports were dropped silently. REALITY, Trojan or VLESS over TLS on 443 fit that pattern; a config on a custom port may not.
2. **Prefer TCP.** Outside DNS, UDP was dropped in those tests. Hysteria 2, TUIC and WireGuard-based protocols run over UDP, and v2rc does not import them anyway.
3. **Expect addresses to be blocked quickly.** Keep spare configs from different hosts and refresh your subscription. Do not post configs in public channels: the more people use an address, the sooner it is blocked.
4. **Test on every connection you use.** Enforcement has differed between networks, so a config that works on mobile data may fail on home broadband and the other way round.
5. **Be careful with free configs from channels.** Strangers run those servers and can see which sites you visit. See [what a proxy hides and what it does not](https://v2rc.app/learn/privacy/).
6. **Accept the limit.** An Iran International analysis puts it plainly: no single tool defeats a full shutdown, and what works is redundancy. When international connectivity is cut altogether, no client helps. Keep what you need available offline.

## Where to check the current state

Live monitors show whether Iran is connected right now: [Cloudflare Radar](https://radar.cloudflare.com/ir) and [IODA](https://ioda.inetintel.cc.gatech.edu/country/IR). Both measure connectivity, not which protocols work.

## Sources

- arXiv: [Iran's Stealth Internet Blackout: A New Model of Censorship](https://arxiv.org/abs/2507.14183) (July 2025)
- arXiv: [Iran's January 2026 Internet Shutdown: Public Data, Censorship Methods, and Circumvention Techniques](https://arxiv.org/abs/2603.28753) (March 2026)
- Amnezia: [Internet censorship in Iran, Q1 2026 and forecast](https://amnezia.org/en/blog/internet-censorship-in-iran-q1-2026-and-forecast) (tool vendor)
- Iran International: [How to beat Iran's internet kill switch](https://www.iranintl.com/en/202605063340) (opinion)