# mii-tool

## 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.
    


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