Android USB tethering

''Tethering means sharing the Internet connection of an Internet-capable mobile phone with other devices. This sharing can be offered over a wireless LAN (Wi-Fi), or over Bluetooth, or by physical connection using a cable'' (Tethering).

The focus of this article is USB tethering.

Android mobile phones can behave as an external network interface usbN, connected via the USB infrastructure. The usbN interface is in turn connected to the mobile phone LAN, providing dhcp server, DNS server, gateway and so on.

That is how a mobile phone can provide an Internet connection to another device.

Android phones are already equipped to provide this functionality. Simply connect the USB cable and go to.

What you need is some kernel and network configuration on the other side (e.g. a laptop).

Version 4.4.6
Features can either be built-in to the kernel or available as loadable modules.

Tested devices

 * Fairphone 2 (Fairphone OS Android 6.0.1, build no FP2-gms-18.04.1) -- needed rndis_host module Processus42 (talk) 18:55, 11 October 2018 (UTC)
 * Google Nexus One (Android 2.3.6 build GRK39F)
 * Google Nexus 4 (Android 4.3 build JWR66Y - uses rndis_host)
 * HTC Desire HD (Android 2.3.6 Stock Rom build and Android 4.4.4 (unofficial CyanogenMod 11) -- needed rndis_host module for both Roms)
 * HTC One M7 (Sense 5.5, Android 4.3, Software number 3.62.401.1,HTC SDK API level 5.65 - I used rndis_host, cdc_ether and usbnet modules ONLY to get it to work)
 * Huawei Honor 4x (unofficial CyanogenMod 11 / Android 4.4.4, works great) -- needed rndis_host module AleiPhoenix (talk) 13:57, 3 July 2015 (UTC)
 * Huawei P10 (Android 8.0.0 stock), Jjmonrod (talk) 23:49, 5 March 2019 (UTC)
 * LG P350 (Android 2.2.1 build FRG83)
 * LG E400 (Android 2.3.6 build GRK39F)
 * LG L7 P705 (Android 4.1.2 build JZO54K)
 * Motorola Defy (Android 2.3.7 Cyanogenmod 7)
 * Motorola Moto G 4G 2013 (1st Gen) (Android 5.1) -- needed rndis_host module -- User:mercuriete
 * OnePlus One -- needed rndis_host module
 * Samsung Galaxy Grand Neo+ Duos (GT-I9060I / Android 4.4.4) -- onli needed rndis_host - cdc_ether - usbnet modules
 * Samsung Galaxy Nexus i9250 (Android 4.0.1 ITL41D, Android 6.0.1 (CyanogenMod 13)) -- needed rndis_host - Ant P. (talk) 00:12, 27 October 2018 (UTC)
 * Samsung Galaxy S i9000
 * Samsung Galaxy S2
 * Samsung Galaxy S3 (GT-I9300 Android 4.3 Stock Rom)
 * Samsung Galaxy S4 Mini Duos (GT-I9192, unofficial CyanogenMod 12.1 / Android 5.1) -- needed rndis_host module
 * Samsung Galaxy S5 (Android 6.0.1) -- needed rndis_host module
 * Samsung Galaxy S6 (Android 7.0) -- needed rndis_host module
 * Samsung Galaxy S7 -- needed rndis_host module
 * Samsung Galaxy Tab 2 7.0 (android 4.1.2)
 * Sony Xperia Go (St27i Android 4.1.2 Stock Rom build no 6.2.A.1.100 -- needed rndis_host module for me - User:LordVan )
 * Sony Xperia X Compact (Android 8.0.0, build no 34.4.A.2.118) -- needed rndis_host module and "Embedded ARM Linux links" (CONFIG_USB_ARMLINUX) on kernel 4.16.18 - Ahippo (talk) 18:58, 25 October 2018 (UTC)
 * Sony Xperia XZ Premium (G8142 Stock Android 8.0, build no 47.1.A.8.49) -- needed rndis_host module AleiPhoenix (talk) 06:56, 29 January 2018 (UTC)
 * Wileyfox Storm (CyanogenOS 13.1.5 - android 6.0.1)
 * Xiaomi Redmi 5 (MIUI 9, 10 and 11)

Testing
If you see usb0 (0 may be a different number) you are all set.

Connecting
Since the mobile phone LAN changes its addresses, you need a DHCP client to configure the usbN device.

If you are on a laptop, you probably have a DHCP client. If not, emerge :

Manually
Simply run after plug/mobile activation:

Permanent configuration
Edit your to have a permanent, automatic activation of the interface.

Once plugged in and activated on the mobile phone side, the usb0 will be up and configured.

Checks
Run the usual checks to verify the connection:

Advanced network settings
DHCP is very quick, but the default settings don't give you as much freedom as you may want.

A possible scenario is that you are in a corporate, protected LAN context that doesn't provide Internet connection but you need to stay connected to have access to some Intranet resource.

Or maybe you have a free but limited connection (a public WiFi network allowing HTTP only, an evil firewall, etc.). Since mobile connections could be expensive, you could want to save money by tethering only when needed.

Here is a handful of examples pertaining to DHCP usage.

If you want to limit the information set by DHCP, you can fine-tune its behaviour.

E.g.:

This will let your default gateway, and hostname as they are, letting you provide extra info by hand.

E.g.:

Finally, you can permanently configure your USB network interface.

E.g:

Generally, you can avoid every DHCP setting (see the man page) but gather them with:

Then you can set what you want in the  hook.