ifquery

ifquery [options] interface

ifquery queries network interface configuration as defined in /etc/network/interfaces and its interfaces.d/ drop-in directory. It is read-only and never modifies interface state.When called without --state, it parses the configuration file and prints the stanzas matching the given interface(s). With --state, it reads /run/network/ifstate to show which interfaces are currently marked as up.On systems using ifupdown2 (common on newer Debian/Ubuntu), additional features are available including --check to compare running state against configuration and JSON output.

INTERFACE

Network interface name to query.

Query all interfaces marked auto in the configuration.

List matching interface names instead of printing their configuration. Combine with --all or --allow to filter.

Query the state file (/run/network/ifstate) for currently active interfaces rather than the configuration file.

Compare running interface state against its configuration and report differences (ifupdown2 only).

Only match interfaces in the given allow class (e.g. auto, hotplug).

Read configuration from FILE instead of /etc/network/interfaces.

Force the operation (used with some queries in ifupdown2).

Display version information.

Display help information.

Debian/Ubuntu specific; part of the ifupdown (or ifupdown2) package. Only reads configuration and state files; never changes anything. The --check flag is only available in ifupdown2. Systems using NetworkManager or systemd-networkd may not use /etc/network/interfaces at all.

ifup(8), ifdown(8)