# Security system configuration

Source: [https://docs.qualcomm.com/doc/80-41102-1/topic/security-system-configuration.html](https://docs.qualcomm.com/doc/80-41102-1/topic/security-system-configuration.html)

The Diag service exposes UDP port 13400 on all network interfaces. Configure the system
            firewall to block UDP traffic destined for port 13400 on all interfaces except those
            used by the Diag service.

For example, if the Diag service is enabled and UDP port 13400 shouldn't be exposed on
            wlan0, configure the following firewall rule:

    iptables -A INPUT -i wlan0 -p udp --dport 13400 -j DROPCopy to clipboard

**Parent Topic:** [TelAF diagnostic](https://docs.qualcomm.com/doc/80-41102-1/topic/telaf_diagnostic.html)

Last Published: Aug 06, 2026

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