mii-tool - view, manipulate media-independent interface status
] [ -V
] [ -r
] [ -w
] [ -l
] [ -A
] [ -F
] interface ...
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
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
options can be used to force the MII to operate in one mode,
instead of autonegotiating. The -A
options are mutually
The default short output reports the negotiated link speed and link status for
- -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
- -A 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
- 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
- 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.
David Hinds - firstname.lastname@example.org
Donald Becker - email@example.com
Bernd Eckenfels - firstname.lastname@example.org
http://net-tools.sourceforge.net - Homepage of the net-tools project