# ifdown(8) - man - phpMan [ifup(8)](https://www.chedong.com/phpMan.php/man/ifup/8/markdown) [ifup(8)](https://www.chedong.com/phpMan.php/man/ifup/8/markdown) ## NAME ifup - bring a network interface up ifdown - take a network interface down ifquery - parse interface configuration ## SYNOPSIS **ifup** [**-nv**] [**--no-act**] [**--verbose**] [**-i** _FILE_|**--interfaces=**_FILE_] [**--state-dir=**_DIR_] [**--allow** _CLASS_] **-a**|_IFACE_... **ifup** **-h**|**--help** **ifup** **-V**|**--version** **ifdown** [**-nv**] [**--no-act**] [**--verbose**] [**-i** _FILE_|**--interfaces=**_FILE_] [**--state-dir=**_DIR_] [**--allow** _CLASS_] **-a**|_IFACE_... **ifquery** [**-nv**] [**--verbose**] [**-i** _FILE_|**--interfaces=**_FILE_] [**--state-dir=**_DIR_] [**--allow** _CLASS_] _IFACE_... **ifquery** **-l**|**--list** [**-nv**] [**--verbose**] [**-i** _FILE_|**--interfaces=**_FILE_] [**--state-dir=**_DIR_] [**--allow** _CLASS_] [**-a**|_IFACE_...] **ifquery** **--state** [**--state-dir=**_DIR_] [**--allow** _CLASS_] [**-a**|_IFACE_...] ## DESCRIPTION The **ifup** and **ifdown** commands may be used to configure (or, respectively, deconfigure) network interfaces based on interface definitions in the file _/etc/network/interfaces_. **ifquery** com‐ mand may be used to parse interfaces configuration. ## OPTIONS A summary of options is included below. ### -a --all If given to **ifup**, affect all interfaces marked **auto**. Interfaces are brought up in the order in which they are defined in _/etc/network/interfaces_. Combined with **--allow**, acts on all interfaces of a specified class instead. If given to **ifdown**, affect all defined interfaces. Interfaces are brought down in the order in which they are cur‐ rently listed in the state file. Only interfaces defined in _/etc/network/interfaces_ will be brought down. ### --force Force configuration or deconfiguration of the interface. ### --ignore-errors If any of the commands of scripts fails, continue. ### -h --help Show summary of options. **--allow=**_CLASS_ Only allow interfaces listed in an _allow-CLASS_ line in _/etc/network/interfaces_ to be acted upon. ### -i --interfaces= Read interface definitions from _FILE_ instead of from _/etc/network/interfaces_. **--state-dir=**_DIR_ Keep interface state in _DIR_ instead of in _/run/network_. ### -X --exclude= Exclude interfaces from the list of interfaces to operate on by the _PATTERN_. _PATTERN_ uses a usual shell glob syntax. If shell wildcards are not used, it must match the ex‐ act interface name. This option may be specified multiple times resulting in more than one pattern being excluded. ### -o Set _OPTION_ to _VALUE_ as though it were in _/etc/network/interfaces_. ### -n --no-act Don't configure any interfaces or run any "up" or "down" commands. ### --no-mappings Don't run any mappings. See [**interfaces**(5)](https://www.chedong.com/phpMan.php/man/interfaces/5/markdown) for more information about the mapping fea‐ ture. ### --no-scripts Don't run any scripts under /etc/network/if-*.d/ ### --no-loopback Disable special handling of the loopback interface. By default, the loopback interface (_lo_ on Linux) is predefined internally as an auto interface, so it's brought up on **ifup** **-a** automatically. In the case the loopback device is redefined by user, the in‐ terface is configured just once anyway. If, however, another interface is also defined as loopback, it's configured as usual. Specifying this option disables this behaviour, so the loopback interface won't be configured automatically. ### -V --version Show copyright and version information. ### -v --verbose Show commands as they are executed. ### -l --list For **ifquery**, list all the interfaces which match the specified class. If no class specified, prints all the interfaces listed as **auto**. ### --state For **ifquery**, dump the state of the interfaces. When no interfaces specified, lists all interfaces brought up together with logical interfaces assigned to them and exits with a status code indicating success. If one or more interfaces specified, display state of these interfaces only; successful code is returned if all of interfaces given as arguments are up. Otherwise, 0 is returned. ## EXAMPLES ### ifup -a Bring up all the interfaces defined with _auto_ in _/etc/network/interfaces_ ### ifup eth0 Bring up interface **eth0** ### ifup eth0=home Bring up interface **eth0** as logical interface **home** ### ifdown -a Bring down all interfaces that are currently up. ### ifquery -l Print names of all interfaces specified with the **auto** keyword. ### ifquery -l --allow=hotplug Print names of all interfaces specified with the **allow-hotplug** keyword. ### ifquery eth0 Display the interface options as specified in the **ifupdown** configuration. Each key- value pair is printed out on individual line using "**:** " as separator. ## NOTES **ifup**, **ifdown**, and **ifquery** are actually the same program called by different names. The program does not configure network interfaces directly; it runs low level utilities such as **ip** to do its dirty work. When invoked, **ifdown** checks if **ifup** is still running. In that case, **SIGTERM** is sent to ifup. During interface deconfiguration, **ifdown** ignores errors the same way as if **--ignore-errors** was specified. ## FILES _/etc/network/interfaces_ definitions of network interfaces See [**interfaces**(5)](https://www.chedong.com/phpMan.php/man/interfaces/5/markdown) for more information. _/run/network/ifstate_ current state of network interfaces ## CONCURRENCY Ifupdown uses per-interface locking to ensure that concurrent ifup and ifdown calls to the same interface are run in serial. However, calls to different interfaces will be able to run in parallel. ## EXIT STATUS For **ifup** and **ifdown**, the exit status will be 0 if the given interface(s) have all been (de)configured successfully, 1 if there was any error. The result of these commands is idem‐ potent; running **ifup** on an interface that is already up will result in an exit status of 0, and similarly running **ifdown** on an interface that is not up will also result in an exit sta‐ tus of 0. **ifquery** will normally return with exit status 0 if an interface with a matching iface stanza, 1 if there is no matching stanza. **ifquery** **--state** will also return with exit status 1 if the given interface was known but was not up. ## KNOWN BUGS/LIMITATIONS The program keeps records of whether network interfaces are up or down. Under exceptional circumstances these records can become inconsistent with the real states of the interfaces. For example, an interface that was brought up using **ifup** and later deconfigured using **ifcon**‐‐ **fig** will still be recorded as up. To fix this you can use the **--force** option to force **ifup** or **ifdown** to run configuration or deconfiguration commands despite what it considers the cur‐ rent state of the interface to be. The file _/run/network/ifstate_ must be writable for **ifup** or **ifdown** to work properly. If that location is not writable (for example, because the root filesystem is mounted read-only for system recovery) then _/run/network/ifstate_ should be made a symbolic link to a writable loca‐ tion. If that is not possible then you can use the **--force** option to run configuration or deconfiguration commands without updating the file. Note that the program does not run automatically: **ifup** alone does not bring up interfaces that appear as a result of hardware being installed and **ifdown** alone does not bring down in‐ terfaces that disappear as a result of hardware being removed. To automate the configuration of network interfaces you need to install other packages such as [**udev**(7)](https://www.chedong.com/phpMan.php/man/udev/7/markdown) or [**ifplugd**(8)](https://www.chedong.com/phpMan.php/man/ifplugd/8/markdown). ## AUTHORS The ifupdown suite was created by Anthony Towns <>, currently main‐ tained by Santiago Ruano Rincón <> and Josue Ortega <> Many others have helped develop ifupdown over time, see /usr/share/doc/ifupdown/changelog.De‐ bian.gz for a full history. ## SEE ALSO [**interfaces**(5)](https://www.chedong.com/phpMan.php/man/interfaces/5/markdown), [**ip**(8)](https://www.chedong.com/phpMan.php/man/ip/8/markdown), [**ifconfig**(8)](https://www.chedong.com/phpMan.php/man/ifconfig/8/markdown). IFUPDOWN 11 Jan 2017 [ifup(8)](https://www.chedong.com/phpMan.php/man/ifup/8/markdown)