Network Configuration for IT Teams
Network Configuration for IT Teams
This guide provides the network requirements IT administrators need to ensure JustCall calls and messaging work reliably across your organization.
Available on: All plans
Required domains (allowlist)
Add the following domains to your firewall and proxy allowlists:
| Domain | Purpose |
|---|---|
*.justcall.io | JustCall application, API, and dashboard |
*.twilio.com | Voice infrastructure and media relay |
*.twilio.com (WebSocket) | Real-time signaling |
*.google.com | SSO and analytics |
*.googleapis.com | Push notifications and integrations |
*.gstatic.com | Static assets |
*.sentry.io | Error reporting |
Required ports
| Protocol | Port range | Direction | Purpose |
|---|---|---|---|
| TCP | 443 | Outbound | HTTPS — app, API, signaling |
| UDP | 10000-60000 | Outbound | RTP — voice media |
| TCP | 5349 | Outbound | TURN over TLS (fallback when UDP is blocked) |
| UDP | 3478 | Outbound | STUN — NAT traversal |
Critical: If UDP ports 10000-60000 are blocked, voice calls will attempt to fall back to TCP, resulting in degraded audio quality. Always allow UDP for best performance.
Bandwidth requirements
| Scenario | Minimum (per call) | Recommended (per call) |
|---|---|---|
| Single voice call | 100 Kbps up/down | 256 Kbps up/down |
| Call + screen sharing | 300 Kbps up/down | 1 Mbps up/down |
| 10 concurrent calls | 1 Mbps up/down | 2.5 Mbps up/down |
| 50 concurrent calls | 5 Mbps up/down | 12.5 Mbps up/down |
Multiply by the peak number of concurrent calls in your office to determine total bandwidth allocation.
Quality of Service (QoS) settings
For the best call quality, prioritize JustCall voice traffic on your network:
- Classify UDP traffic on ports 10000-60000 as real-time voice.
- Set DSCP marking to EF (Expedited Forwarding, DSCP 46) for these packets.
- Prioritize this traffic class above general web browsing and file downloads.
- Reserve bandwidth — allocate dedicated bandwidth for voice traffic so it is not competing with large file transfers or video streaming.
VPN recommendations
VPNs add latency and can cause call quality issues. If your organization requires VPN:
- Split tunneling (recommended): Configure the VPN to exclude JustCall and Twilio traffic. Route
*.justcall.ioand*.twilio.comdirectly over the local internet connection. - Full tunnel: If split tunneling is not possible, ensure the VPN endpoint is geographically close to your users. Avoid routing voice traffic through distant VPN servers.
- UDP support: Verify the VPN passes UDP traffic. Some VPNs only support TCP, which degrades voice quality.
Proxy server configuration
If your network uses an HTTP proxy:
- JustCall web traffic (TCP 443) can pass through the proxy.
- Voice media (UDP) cannot pass through an HTTP proxy — ensure UDP traffic bypasses the proxy entirely.
- Add
*.justcall.ioand*.twilio.comto the proxy bypass list.
Verification
After configuring your network, verify connectivity:
- Have an agent log into JustCall and run the network test at Settings > Network Test.
- Confirm bandwidth, latency, jitter, and packet loss are within acceptable ranges.
- Make a test call (both inbound and outbound) and verify two-way audio.