How to configure your first SIP trunk

To receive and place calls you need at least one SIP trunk connecting SIVO to your carrier. SIVO is not a telco: you choose your carrier and pay them directly.

Steps

1. In the dashboard, go to Settings → SIP trunks → + New trunk.
2. Pick your carrier (zadarma, twilio, bandwidth or custom).
3. Fill in:
   • Name: e.g. zadarma-prod.
   • Carrier host: e.g. sip.zadarma.com.
   • User + password: the SIP credentials your carrier provided.
   • Allowed CIDRs: the IP ranges your carrier uses to send calls.
4. Save. Status turns REGED within 30s if credentials are correct.

Typical CIDRs per carrier

Carrier	CIDRs
Zadarma	185.45.152.0/24 (full range, not just 185.45.152.180)
Twilio	See Twilio dashboard → Elastic SIP Trunking → IP ACL
Bandwidth	Provided during your Bandwidth onboarding

If the trunk stays in FAIL

90% of cases:

• Incomplete CIDR — Zadarma needs full /24, not single IP.
• Wrong credentials — copy/paste exactly as the carrier provided (watch for spaces).
• Firewall — verify outbound 5060/UDP is open from SIVO to the carrier.

→ See full troubleshooting for extreme cases.