The udp_block parameter is responsible for blocking the UDP protocol for services that primarily process TCP traffic while allowing UDP traffic to pass through without processing.

Examples of such services:

• Service 4 Filtering by a list of restricted sites
• Services 5 and 16 Allow list and Captive Portal

If the udp_block parameter is present in the DPI configuration file /etc/dpi/fastdpi.conf, both TCP and UDP traffic are blocked. If the parameter is absent, only TCP traffic is blocked.

To start blocking UDP protocols (for example, QUIC), add the udp_block parameter with the value 2 or 3 to the configuration file (start blocking after two or three UDP packets have passed). It is also possible to start processing from the very first UDP packet, but this may increase the load on the DPI during a DDoS attack.

udp_block=3

Adding the parameter does not require restarting the DPI. It is sufficient to perform a reload:

service fastdpi reload

To completely disable UDP traffic processing:

only_tcp=1

Default value: only_tcp=0 — UDP traffic processing is enabled.