VoIP and SIP security
A phone system on the internet is a target. Attackers scan for open SIP ports, guess extension passwords and place calls to premium-rate numbers on the company's bill. A weekend of toll fraud can cost more than the phone system.
What we do
- SBC placement design
- Toll-fraud limits
- Trunk allow-lists
- Call record alerts
- STIR/SHAKEN readiness
- SIP scan blocking
- E911 checks
Our team works with AudioCodes session border controllers, Kamailio, OpenSIPS and FreeSWITCH, and has experience with ATIS standards for STIR/SHAKEN caller authentication. We put an SBC at the edge, restrict calling by country and time, use TLS for signalling and SRTP for media, and set alerts on unusual call patterns.
This group links to our Communications and Voice service and to the voice and UC groups. These are tools our team has experience with, not partnerships.
Leading platforms we work with
- AudioCodes
- Kamailio
- OpenSIPS
- FreeSWITCH
- ATIS
- Ribbon Communications
- Asterisk
- Oracle Session Border Controller
Platforms and practices
- Session border controllers
- SIP over TLS and SRTP
- Toll-fraud call limits and country blocks
- STIR/SHAKEN caller authentication
- SIP trunk allow-lists
- Extension password hardening
- Call detail record monitoring
- Voicemail and conference bridge lockdown
- Emergency calling and E911 location checks
References
Sources last checked .
Product names are trademarks of their owners and are listed to describe our experience; they do not imply endorsement or partnership.
How we use VoIP and SIP security for clients
Voice, Fax & SMS
One platform for business voice, fax and text messaging, connected to your ERP, your Microsoft Teams and the software we build for you.
Learn moreCybersecurity
We find out whether everything you run is safe from attackers, then we fix it.
Learn moreManaged IT Services
We run your IT day to day so it stays secure: help desk, devices, Microsoft 365, Exchange, Active Directory, backups, networks and monitoring.
Learn moreFrequently asked questions
Direct answers to the questions we hear most. Something else on your mind?
Send us a messageWhat is toll fraud?
Toll fraud is when an attacker gets into a phone system and places calls, often to premium-rate or international numbers, that you pay for. It often happens on weekends. Country blocks, call limits and alerts on unusual call patterns reduce the damage.
What does a session border controller do?
A session border controller (SBC) sits between your phone system and the internet or your SIP trunk provider. It accepts calls only from approved sources, hides the internal network, and can enforce encryption and call limits. It also gives you one place to log and block scanning.
Does STIR/SHAKEN stop spoofed calls to us?
Not by itself. STIR/SHAKEN lets carriers sign calls so the receiving carrier can check whether the caller ID is trusted. It mainly helps your outbound calls be marked as legitimate. Whether it is required for your numbers depends on your carrier and current FCC rules, so confirm with your carrier.
Can you check that emergency calling still works after changes?
Yes, we include E911 location checks, because moves, extensions and remote phones can send the wrong address. Testing has to be coordinated with your provider and the local emergency service rules, so we plan it with you before placing any test calls.