Related articles * [Network configuration](/index.php/Network_configuration "Network configuration") * [Wireless network configuration](/index.php/Wireless_network_configuration "Wireless network configuration") * [Software access point](/index.php/Software_access_point "Software access point") * [Internet sharing](/index.php/Internet_sharing "Internet sharing") An IBSS (Independent Basic Service Set) network, often called an ad-hoc network, is a way to have a group of devices talk to each other wirelessly, without a central controller. It is an example of a peer-to-peer network, in which all devices talk directly to each other, with no inherent relaying. For example, ad-hoc networking may be used to [share an internet connection](/index.php/Internet_sharing "Internet sharing"). ## Contents * [1 Requirements](#Requirements) * [2 Wifi link layer](#Wifi_link_layer) * [2.1 Manual method](#Manual_method) * [2.2 WPA supplicant](#WPA_supplicant) * [3 Network configuration](#Network_configuration) * [4 Tips and tricks](#Tips_and_tricks) * [4.1 Using NetworkManager](#Using_NetworkManager) * [4.2 Custom systemd service (with wpa_supplicant and static IP)](#Custom_systemd_service_.28with_wpa_supplicant_and_static_IP.29) * [5 See also](#See_also) ## Requirements * A [nl80211 compatible](https://wireless.wiki.kernel.org/en/users/drivers%7C) wireless device (e.g. ath9k) on all devices which will connect to the network ## Wifi link layer Since IBSS network is a peer-to-peer network, the steps necessary to set up the wifi link layer should be the same on all devices. **Tip:** It is possible to create complex network topologies, see [Linux Wireless documentation](http://wireless.kernel.org/en/users/Documentation/iw/vif) for advanced examples. ### Manual method **Warning:** This method creates **unencrypted** ad-hoc network. See [#WPA supplicant](#WPA_supplicant) for method using WPA encryption. See [Wireless network configuration#Manual setup](/index.php/Wireless_network_configuration#Manual_setup "Wireless network configuration") for a better explanation of the following commands. Make sure that [iw](https://www.archlinux.org/packages/?name=iw) is [installed](/index.php/Pacman "Pacman"). Set the operation mode to ibss: ``` # iw *interface* set type ibss ``` Bring the interface up (an additional step like `rfkill unblock wifi` might be needed): ``` # ip link set *interface* up ``` Now you can create an ad-hoc network. Replace *your_ssid* with the name of the network and *frequency* with the frequency in MHz, depending on which channel you want to use. See the Wikipedia page [List of WLAN channels](https://en.wikipedia.org/wiki/List_of_WLAN_channels#Interference_Concerns "wikipedia:List of WLAN channels") for a table showing frequencies of individual channels. ``` # iw *interface* ibss join *your_ssid* *frequency* ``` ### WPA supplicant Ensure that [wpa_supplicant](https://www.archlinux.org/packages/?name=wpa_supplicant) is [installed](/index.php/Pacman "Pacman"), and create a configuration file for it (see [WPA supplicant](/index.php/WPA_supplicant "WPA supplicant") for details). `/etc/wpa_supplicant-adhoc.conf` ``` ctrl_interface=DIR=/run/wpa_supplicant GROUP=wheel # use 'ap_scan=2' on all devices connected to the network # this is unnecessary if you only want the network to be created when no other networks are available ap_scan=2 network={ ssid="MySSID" mode=1 frequency=2432 proto=RSN key_mgmt=WPA-PSK pairwise=CCMP group=CCMP psk="secret passphrase" } ``` Run *wpa_supplicant* on all devices connected to the network with the following command: ``` # wpa_supplicant -B -i *interface* -c /etc/wpa_supplicant-adhoc.conf -D nl80211,wext ``` ## Network configuration The final step is to assign an IP address to all devices in the network. There are multiple ways to do this: * Assign static IP addresses. See [Network configuration#Static IP address](/index.php/Network_configuration#Static_IP_address "Network configuration") for details. * Running DHCP server on one device. See [dhcpd](/index.php/Dhcpd "Dhcpd") or [dnsmasq](/index.php/Dnsmasq "Dnsmasq") for details. * Running *avahi-autoipd*. See [Avahi#Obtaining IPv4LL IP address](/index.php/Avahi#Obtaining_IPv4LL_IP_address "Avahi") for details. If you want to share an internet connection to the ad-hoc network, see [Internet sharing](/index.php/Internet_sharing "Internet sharing"). ## Tips and tricks ### Using NetworkManager If you use [NetworkManager](/index.php/NetworkManager "NetworkManager"), you can use *nm-applet* for ad-hoc network configuration instead of the manual method described above. See [NetworkManager#Ad-hoc](/index.php/NetworkManager#Ad-hoc "NetworkManager") for details. **Note:** NetworkManager does not support WPA encryption in ad-hoc mode. ### Custom systemd service (with wpa_supplicant and static IP) You can use the following templates to enable wireless ad-hoc networking: `/etc/conf.d/network-wireless-adhoc@` ``` addr=192.168.0.2 mask=24 ``` `/etc/systemd/system/network-wireless-adhoc@.service` ``` [Unit] Description=Ad-hoc wireless network connectivity (%i) Wants=network.target Before=network.target BindsTo=sys-subsystem-net-devices-%i.device After=sys-subsystem-net-devices-%i.device [Service] Type=oneshot RemainAfterExit=yes EnvironmentFile=/etc/conf.d/network-wireless-adhoc@%i # perhaps rfkill is not needed for you ExecStart=/usr/bin/rfkill unblock wifi ExecStart=/usr/bin/ip link set %i up ExecStart=/usr/bin/wpa_supplicant -B -i %i -D nl80211,wext -c /etc/wpa_supplicant-adhoc.conf ExecStart=/usr/bin/ip addr add ${addr}/${mask} dev %i ExecStop=/usr/bin/ip addr flush dev %i ExecStop=/usr/bin/ip link set %i down [Install] WantedBy=multi-user.target ``` ## See also * [Ubuntu community wiki WifiDocs/Adhoc](https://help.ubuntu.com/community/WifiDocs/Adhoc) * [Manual about creating an Ad-Hoc network on UbuntuGeek](http://www.ubuntugeek.com/creating-an-adhoc-host-with-ubuntu.html) * [Share your 3G Internet connection over wifi](http://go2linux.garron.me/linux/2011/03/share-your-3g-internet-connection-over-wifi-linux-ipod-touch-925)