SMS Firewall

SMS spam, fraud and unwanted A2P traffic erode subscriber trust and drain operator revenue. The Netfors SMS Firewall stops unwanted messages before they reach your subscribers: every incoming SMS is inspected and filtered according to your policy — on the same proven Netfors SMSC platform.

Netfors SMS Firewall: an incoming SMS for subscriber B is routed via the HLR to the Netfors SMS Firewall (Netfors SMSC with firewall add-on), which applies policy — spam filter, sender-ID screening, content rules — before allowed messages are delivered via the MSC/VLR. All application interfaces are covered: SMPP, HTTP, SMTP, IP-SM-GW (SIP) and the Plugin API.

Stop SMS spam and fraud before delivery

The SMS Firewall applies your policy to every incoming SMS:

  • Spam and scam filtering on all incoming messages
  • Sender-ID / originator screening to block spoofed and unauthorized senders
  • Content and keyword rules
  • Flexible actions per rule: deliver, divert, block, or log/alert
  • Open-ended custom filtering: the Plugin API add-on lets you run your own filtering logic on selected messages — it can even call out to an LLM for edge cases and novel abuse patterns

One firewall policy for all SMS traffic

All application interfaces of the Netfors SMSC are covered: SMPP, HTTP, SMTP, IP-SM-GW and the Plugin API. SIP-originated and SIP-terminated SMS (VoLTE, VoWiFi and IMS) are converted to MAP by the Netfors IP-SM-GW interface option, so the same firewall policy applies to all of your SMS traffic — managed from one web-based user interface.

How it works

  1. The HLR (or STP) of the home network is programmed to return the SMS Firewall as the serving node for all incoming SMS, instead of the MSC.
  2. The originating SMSC asks the HLR where the destination mobile is located (SRI for SM) and receives the address of the SMS Firewall.
  3. The SMS is forwarded to the SMS Firewall, which applies your policy: spam filter, sender-ID/originator screening, and content and keyword rules — then delivers, diverts, blocks, or logs/alerts on the message.
  4. Allowed messages are sent on towards the MSC/VLR, and delivery status is reported back to the SMS Firewall.
  5. The SMS is delivered to the recipient.

An add-on to the proven Netfors SMSC platform

The SMS Firewall is not a new platform — it is the Netfors SMS Center (SMSC) with the SMS Firewall add-on license. It builds on the same high-availability SMSC platform and complements SMS home routing, which directs all inbound SMS through the Netfors SMSC.

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