> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://support.callers.io/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# How to unblock callers.io servers

Some office networks block voice/call services.

If calls are not ringing, not connecting, or audio is failing, your office firewall may be blocking Callers.io or our call delivery system.

We use LiveKit to deliver live calls in the browser.

We also use PostHog to track app errors and understand what went wrong.

Please ask your office IT/network admin to allow the items below.

## Please contact your office network admin and request to unblock the following.

Please allow:
```
*.callers.io
*.livekit.cloud
*.turn.livekit.cloud
*.host.livekit.cloud
eyes.callers.io
```
And allow these outbound ports:
```
TCP 443
TCP 7881
UDP 3478
UDP 50000-60000
```


## Detailed Explanation about each of the above domains :  


| Service | Domain / Host | Port | Why it is needed |
| ---- |
| Call delivery | `*.livekit.cloud` | TCP 443 | Secure WebSocket connection for calls |
| Call fallback | `*.turn.livekit.cloud` | TCP 443 | Backup call connection if normal connection fails |
| Call fallback | `*.host.livekit.cloud` | UDP 3478 | Helps connect call audio |
| Call audio | Any host | UDP 50000-60000 | Best quality live call audio |
| Call audio fallback | Any host | TCP 7881 | Backup path for call audio |
| Error tracking / analytics | `eyes.callers.io` | TCP 443 | Helps us see errors and fix issues |