Intelligent CLI Validation


Сontrol your surcharges

Block invalid CLIs by rejecting non-conforming calls.

Helping Operators Providers Telcos to conform with UK Ofcom rules

Also for users operating basic and open-source equipment with limited control over CLI manipulation and presentation.


New Ofcom CLI Rules

Ofcom CLI rules can lead to surcharges on calls terminating in the UK. As part of their attempt to reduce spam and telecoms fraud from 1st August 2021, regulator Ofcom introduced new origin-based surcharges for internationally originated calls to UK geographic (starting 01/08/2021) or mobile numbers (starting 01/09/2021).

Surcharges have to be applied where a CLI is missing, corrupt, malformed or unknown. Pre-defined charge bands apply based on destination (UK mobile/fixed) and vary by source country code and can be as high as £2 per minute.
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CLI Validation Service stops non-conforming calls

By using Netaxis CLI Validation, Service Providers in the UK can prevent calls that would attract a surcharge from being completed. The service rejects calls with missing, corrupt, malformed or unknown CLIs and, using a tabular lookup, applies the relevant charge band for allowable calls. Block invalid CLIs!
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How we do it

For a UK based CLI, it will verify that it is valid by referencing Ofcom assigned official number ranges. A failure in this verification will cause the call to be rejected (configurable). For a non-UK based CLI, it will match the CLI against a list of surcharge bands, each of which has a different surcharge price per minute, per destination (UK geo vs UK mob). You can define on a customer by customer basis allowable CLI bands.
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No commitment. You can scale up or down as often as you like and stop using the service at any time.

€0.0005/per CLI Lookup
Free trial period PoC environment No minimum commitment

Simple Onboarding

CLI validation as a service is built on the cloud-based SREaaS and can be enabled simply and quickly without investing in new infrastructure.


VPN configuration and optional customisation of default logic and charge band definition, based on your needs or our standard template.


Definition of how your customers are identified in the SIP signaling and the type of network responses they need in the two cases: a) call can proceed, b) call must be rejected.


Control usage of the service from our intuitive web portal and pay monthly via Stripe, with no long term commitment!

Ready to save on surcharges?

It’s simple to set up and quick to enable, but we’re here to answer any questions you may have.