What is a SIP firewall?

A SIP firewall sits in front of your switch or SBC and screens signaling before calls are set up. CallerAPI's firewall checks every INVITE against fraud data refreshed every minute and STIR/SHAKEN attestation, drops bad traffic at the edge, and passes clean calls to your infrastructure.

How is it different from an SBC?

An SBC handles interconnect, media and topology hiding. It doesn't know which numbers are running fraud campaigns right now. The SIP firewall adds that intelligence layer in front: complaint-backed spam verdicts and attestation checks, so your SBC only ever sees traffic worth carrying.

Does the voice firewall use STIR/SHAKEN?

Yes. Blocking decisions factor in STIR/SHAKEN attestation alongside the live spam verdict, and the attestation level of every call is logged so you can audit exactly why traffic was dropped or passed.

How do I deploy the SIP firewall?

Point a SIP domain at the firewall, register your SBC endpoints, and traffic starts flowing through the screen. Calls route to the nearest healthy region, and a live analytics dashboard shows every decision. Plans scale with the number of SBC endpoints.

SIP firewall that drops fraud before your switch

A voice firewall at the network edge: every INVITE is screened against fraud data refreshed every minute and STIR/SHAKEN attestation. Clean calls route through, fraud never burns a channel.

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sip-firewall · live decisions screening

02:41:07 INVITE +18882211161 attest=C  ✕ DROP (603) spam, 43 complaints
02:41:08 INVITE +16502530000 attest=A  ✓ PASS (200) verified business
02:41:08 INVITE +12099009302 attest=B  ✕ DROP (603) robocall campaign
02:41:09 INVITE +447476937994 attest=A ✓ PASS (200) → sbc-us-east
02:41:11 INVITE +18006343169 attest=C  ✕ DROP (603) blacklist hit, 60s old

In the call path, out of your way

Point a SIP domain at the firewall, register your SBC endpoints, done. No switch replacement, no dialplan surgery.

Inbound

All SIP traffic

Every INVITE from carriers, trunks and the open internet hits the firewall first.

Screen

CallerAPI SIP Firewall

Spam verdict from minute-fresh complaint data, STIR/SHAKEN attestation check, block decision logged with origin IP and raw SIP.

Clean out

Your SBC or switch

Passing calls route to the nearest healthy endpoint, region-aware. Fraud never reaches your capacity.

The voice firewall for carriers, VoIP and CPaaS

Firewalls guard your packets. Nothing guards your voice traffic, and fraud rides straight into switches, queues and agents. This is the missing layer.

STIR/SHAKEN aware

Attestation is part of every block decision and every log line, ready for compliance reviews.

Evidence, not vibes

Every drop traces back to consumer complaints, the same data behind our spam call blocking API.

Live analytics

Origin IP, user agent, attestation and decision for every screened call, streaming into your dashboard.

Running a network end to end? See how the firewall, feed and API stack up in telecom fraud prevention.

SIP firewall questions

Put a firewall in front of your voice

Set up a SIP domain and see your first screened calls today, or walk us through your topology first.