DNS tunnels such as SlipNet and StormDNS send your traffic through public DNS resolvers. If the resolvers you use are blocked on your network, the tunnel can't start. This article shows three ways to find resolvers that work for you.
Why this matters
In Iran and other censored countries, well-known resolvers such as Google's 8.8.8.8 or Cloudflare's 1.1.1.1 are often blocked or filtered. Which resolvers work depends on your ISP and on whether you're on Wi-Fi or mobile data, and it changes over time. So it's worth checking from the network you actually use.
Option 1: Scan in the SlipNet app (best for SlipNet)
The SlipNet app tests resolvers from your phone, on your current network, which gives the most reliable result.
- Connect to the network you'll use (home Wi-Fi or mobile data), with no VPN running.
- Open SlipNet and go to Settings › DNS Resolver Scanner.
- In Iran, select Scan IR DNS Lite.
- Wait for the scan to finish. It usually takes a minute or two.
- Use only the resolvers marked E2E Passed. These passed a full end-to-end test, not just a simple reply.
- Note the two or three fastest, or apply them as described in How to Set Your DNS Resolvers in SlipNet.
Option 2: Use our Iran Resolvers list
The portal keeps a list of resolvers verified on Iranian ISPs and mobile operators, refreshed every 6 hours.
- Go to Anti-Censorship › SlipNet › Iran Resolvers. The same list is under Anti-Censorship › StormDNS › Iran Resolvers.
- Search the list if you need to, then click Copy next to a resolver, or use the Copy All button at the bottom to copy the whole list.
- Paste them into your DNS tunnel app's resolver settings (SlipNet, WhiteDNS or PremierNexus).
Results vary by ISP. If one resolver doesn't work, try another.
Option 3: Use the portal DNS Scanner
Go to Anti-Censorship › SlipNet › DNS Scanner. It tests resolvers live from your browser.
- Only DNS-over-HTTPS (port 443) resolvers can be tested from a browser.
- The DNS-over-TLS (port 853) and UDP (port 53) tabs are listed for reference only. Test those in the SlipNet app.
- Click Scan All, then Sort by Speed. When a fastest result is found, use Copy for SlipNet to copy it in
IP:53format.
The SlipNet app's scanner (Option 1) tests the same kind of DNS your tunnel uses, so trust its results over the browser scanner if they disagree.
Tips
- Scan on each network you use. A resolver that works on home Wi-Fi may not work on mobile data.
- If a scan finds nothing, switch between Wi-Fi and mobile data and scan again.
- Resolvers get blocked over time. If a connection that used to work stops, scan again first.
Next step
Put your working resolvers into SlipNet: How to Set Your DNS Resolvers in SlipNet. Using StormDNS instead? See StormDNS on Android with WhiteDNS or PremierNexus on iOS.