Hey! I'm building an AI receptionist service in New Caledonia (French Pacific). My local telecom (OPT/Hélia) only supports SIP trunk authentication via static IP whitelisting — no REGISTER, no username/password. My stack: OPT SIP Trunk → 3CX SBC (Debian VM) → Vapi AI agent I found that Vapi uses 44.229.228.186 and 44.238.177.138 for SIP signaling. A few questions: 1. Can Vapi receive inbound SIP calls authenticated by IP only (no REGISTER)? 2. Are these IPs stable long-term? 3. What's the per-minute cost for inbound SIP calls? 4. Is there an agency/reseller program for managing multiple client agents? Thanks!

Yeah, you’re running into a pretty common issue with carriers that only support IP auth. Vapi isn’t really designed for pure IP-based inbound, so your 3CX SBC is actually the right way to bridge things. Also, those IPs aren’t guaranteed to stay fixed, so relying on whitelisting alone can get risky. Pricing is usually per-minute across voice + AI usage, and there is a partner model if you’re planning to scale this. are you planning to route everything through 3CX, or trying to pass calls directly into Vapi? @Supra

Hi Matt, Thank you very much for the quick response! Yes, the plan is to route everything through 3CX. OPT authenticates via static IP on their end, 3CX receives those calls and forwards them to Vapi — so Vapi only sees traffic coming from my 3CX instance, not directly from my local telecom. Just to confirm: is 3CX → Vapi a fully supported and reliable setup? No known compatibility issues or limitations I should be aware of before I go ahead and build the whole infrastructure around this? Also a few follow-up questions: 1. What’s the recommended way to configure the 3CX → Vapi leg? SIP trunk with credentials on the Vapi side? 2. Any ballpark on per-minute pricing for inbound voice + AI usage? 3. How does the partner/agency model work — sub-accounts under one org, or separate accounts? Thanks!

You’re definitely on the right track , 3CX → Vapi works well in setups like yours, and it’s reliable as long as 3CX handles the SIP side cleanly. I’d recommend connecting 3CX to Vapi using SIP credentials rather than IP for better stability. Pricing is usually per-minute (voice + AI), and you can manage multiple clients under one org with the partner setup. Happy to help you get this fully set up without the guesswork, are you starting small or expecting higher call volume right away? @Supra

Hi @Supra ! Nice to meet you. Are you building a voice AI system routing calls from OPT (a telecom provider authenticating via static IP) through 3CX (a PBX system) to Vapi (a voice AI platform). As a developer with experience in that aspect, i can help you. Can we discuss more detailed via DM?

@Matt Thanks for confirming! Great to know the setup is solid. I’m starting small first 5 to 10 clients. But because I am the first to sell this in my country I expect a big activity development in the next weeks/months. Right now I'm waiting some invoices from local datacenter for the setup. Regarding Vapi, you think I should go with a "partner" setup ? What is that ? @Wapple Yes, that’s exactly what I’m building! Would love to connect via DM — sending you a message now.