Hi Vapi team 👋 I’m connecting a SIP trunk from a carrier with strict anti-fraud rules. They require SIP REGISTER and all outbound calls to originate from the exact same public IP and source port (UDP 5060), otherwise calls are blocked. Can Vapi pin a BYO SIP trunk to one fixed signaling IP and the same source port for both registration and outbound calls? #1211483291191083018

@Sajad VAPI doesn't work like that, their load balancing schemes require the call to be bounced between servers. Your provider is requiring a functionality normally associated with an SBC (Session Border Controller). If you want, I can show you how to resolve this issue using Cloudonix as an in-between.

Hi Sajad, Short answer: no — we cannot guarantee a fixed source port (5060) or pin a BYO SIP trunk to a single Vapi signaling IP/port. Our SIP architecture uses shared servers and load balancing that may change source IPs and ephemeral ports mid-dialog, which breaks providers that strictly require same IP+port. Options: - Use a provider that supports per-customer termination (Plivo, Telnyx, Twilio) or username/password auth — these are known to work with Vapi. See Plivo guide: https://docs.vapi.ai/advanced/sip/plivo - Configure your carrier to accept dynamic source ports / our two static IPs: 44.229.228.186/32 and 44.238.177.138/32 (whitelist both). See SIP trunk docs: https://docs.vapi.ai/advanced/sip/sip-trunk - Insert an intermediary SBC/proxy (e.g., Cloudonix or your own SBC) that registers to the carrier from a single IP:port and proxies traffic to Vapi. This is the recommended workaround for strict anti-fraud SBCs. Can you tell me which carrier you use and whether you can deploy a Cloudonix/SBC

Hi @Nir Simionovich (CEO@Cloudonix) Thank you for your response. It sounds good. I would like to have some support on this matter please. Thank you

Please ping me over a DM

thank you again Nir. if you would like to reopen this ticket, please let us know