red ethernet eth interfaces velocidad

**ANTECEDENTES**

Tenemos una tarjeta de red, y queremos saber si soporta velocidades de 10000mbps ('gigabit')

**SOLUCIÓN**

(Como root)

1. Suponiendo que la tarjeta de red sea 'etho':

  dmesg | grep eth0
  [    1.990066] e1000: eth0: e1000_probe: Intel(R) PRO/1000 Network Connection
  [  536.704969] e1000: eth0: e1000_watchdog: NIC Link is Up 10 Mbps Half Duplex, Flow Control: None
  [  758.407797] eth0: no IPv6 routers present

En este caso va a 10mbps = mojón

Mejor instalar ethtool que te dice todo lo que soporta y a cuanto está ahora:
  #apt-get install ethtool

  # ethtool eth0
  Settings for eth0:
        Supported ports: [ MII ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Advertised auto-negotiation: Yes
        Speed: 100Mb/s
        Duplex: Full
        Port: MII
        PHYAD: 0
        Transceiver: external
        Auto-negotiation: on
        Supports Wake-on: g
        Wake-on: d
        Link detected: yes