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Applying b4 to selected devices

By default b4 handles the traffic of every device on the network. Device filtering under Settings > Core > Devices decides which devices get DPI bypass at all. The Source Devices of a set limit that one set to some devices.

Requirements​

  • The devices are on the router's network, where b4 finds them in the ARP table.
  • A device behind another router has a fixed or reserved IP address, since it can be added only by that address.

Choosing the devices that get DPI bypass​

  1. Open Settings > Core > Devices.
  2. Turn on Enable Device Filtering.
  3. Under Available Devices, select the devices. A device missing from the list is added under Manual Devices by its IP address.
  4. To exclude the selected devices instead of limiting DPI bypass to them, turn on Exclude Selected Devices (Blacklist).
  5. Click Save Changes, then Restart Service. The selection applies after a restart.

What the filter covers:

  • DPI bypass matches devices by MAC address. A device added by hand does not count for it, and a selection made only of such devices leaves DPI bypass on for every device.
  • Routing sets and Telegram over WebSocket use the same selection for traffic from the network. There a device added by hand is matched by its IP address.
  • The router itself is not a device. Its own connections, those of the SOCKS5 proxy included, get DPI bypass in both modes.
  • While devices are selected, sets do not write their own DSCP value.

The fields are described under Devices.

Applying one set to some devices​

  1. Open the set, then Targets > Source Devices.
  2. Select the devices.
  3. To apply the set to every device except the selected ones, turn on All devices except selected.
  4. Save the set.

A set limited to source devices takes priority over a set without that limit. Source devices narrow whom a set applies to, but they do not select traffic. A routing set still needs a domain, IP or ASN target, and Match any IP address under Bypass IPs routes everything from those devices. See Source devices.

Checking the result​

  1. Open Traffic.
  2. In the Devices panel, select a device.
  3. Its connections show the set that matched each of them.

Devices that device filtering leaves out get no DPI bypass, and the dashboard does not count their connections.

When it does not work​

  • Nothing changed after saving. The device filter applies after a restart of b4.
  • A device added by hand gets no DPI bypass. DPI bypass matches MAC addresses only. Such a device can still be the source device of a set.
  • A device added by hand is not matched. Its IP address changed, or a router in between replaces the source address of its traffic. The first needs a fixed or reserved address; the second cannot be matched at all.
  • A phone stops being matched. Many phones use a randomized MAC address, shown as Private, and a new address is a new device for b4. Turning off the private address for this network on the phone keeps its MAC address fixed.