Provided by: net-tools_1.60+git20161116.90da8a0-1ubuntu1_amd64 
NAME
mii-tool - view, manipulate media-independent interface status
SYNOPSIS
mii-tool [-v, --verbose] [-V, --version] [-R, --reset] [-r, --restart] [-w, --watch] [-l, --log] [-A,
--advertise=media,...] [-F, --force=media] [-p, --phy=addr] interface ...
DESCRIPTION
This utility checks or sets the status of a network interface's Media Independent Interface (MII) unit.
Most fast ethernet adapters use an MII to autonegotiate link speed and duplex setting.
Most intelligent network devices use an autonegotiation protocol to communicate what media technologies
they support, and then select the fastest mutually supported media technology. The -A or --advertise
options can be used to tell the MII to only advertise a subset of its capabilities. Some passive
devices, such as single-speed hubs, are unable to autonegotiate. To handle such devices, the MII
protocol also allows for establishing a link by simply detecting either a 10baseT or 100baseT link beat.
The -F or --force options can be used to force the MII to operate in one mode, instead of
autonegotiating. The -A and -F options are mutually exclusive.
The default short output reports the negotiated link speed and link status for each interface.
OPTIONS
-v, --verbose
Display more detailed MII status information. If used twice, also display raw MII register
contents.
Alert: If used three times, will force reading all MII registers, including non standard ones.
It's not guaranteed any valid answer from PHY while PHY communication can even hang. With driver
e1000e will fail while reading register 0x07.
-V, --version
Display program version information.
-R, --reset
Reset the MII to its default configuration.
-r, --restart
Restart autonegotiation.
-w, --watch
Watch interface(s) and report changes in link status. The MII interfaces are polled at one second
intervals.
-l, --log
Used with -w, records link status changes in the system log instead of printing on standard
output.
-F media, --force=media
Disable autonegotiation, and force the MII to either 100baseTx-FD, 100baseTx-HD, 10baseT-FD, or
10baseT-HD operation.
-A media,..., --advertise=media,...
Enable and restart autonegotiation, and advertise only the specified media technologies. Multiple
technologies should be separated by commas. Valid media are 100baseT4, 100baseTx-FD, 100baseTx-
HD, 10baseT-FD, and 10baseT-HD.
-p addr, --phy=addr
Override the MII address provided by kernel with value addr.
DIAGNOSTICS
SIOCGMIIPHY on 'eth?' failed: Invalid argument
If the interface is not running (up), kernel will refuse to report its link state.
SIOCGMIIPHY on 'eth?' failed: Operation not permitted
Most kernels restrict access to root.
SIOCGMIIPHY on 'eth?' failed: No such device
This error is shown, if the kernel does not know about the named device.
SIOCGMIIPHY on 'eth?' failed: Operation not supported
The interface in question does not support MII queries. Most likely, it does not have MII
transceivers, at all.
AUTHORS
David Hinds - dhinds@pcmcia.sourceforge.org Donald Becker - becker@scyld.com Bernd Eckenfels - net-tools@lina.inka.de
SEE ALSO
http://net-tools.sourceforge.net - Homepage of the net-tools project