# dmesg |grep eth0

divert: allocating divert_blk for eth0
eth0:
RealTek RTL8139 at 0xd800, 00:80:48:34:c2:84, IRQ 9
eth0:  Identified 8139 chip type 'RTL-8100B/8139D'
divert: freeing divert_blk for eth0
divert: allocating divert_blk for eth0
eth0: RealTek RTL8139 at 0xd800, 00:90:44:34:a5:33, IRQ 9
eth0:  Identified 8139 chip type 'RTL-8100B/8139D'
eth0: link up, 100Mbps, full-duplex, lpa 0x41E1
eth0: no IPv6 routers present
...

# mii-tool -v eth0

eth0: negotiated 100baseTx-FD, link ok
product info: vendor 00:00:00, model 0 rev 0
basic mode:   autonegotiation enabled
basic status: autonegotiation complete, link ok
capabilities: 100baseTx-FD 100baseTx-HD 10baseT-FD
            10baseT-HD
...

# ethtool eth0

Settings for eth0:
 Supported ports: [ TP MII ]
 Supported link modes:   10baseT/Half 10baseT/Full
                         100baseT/Half 100baseT/Full
 Supports auto-negotiation: Yes
 Advertised link modes:  10baseT/Half 10baseT/Full
                         100baseT/Half 100baseT/Full
 Advertised auto-negotiation: Yes
 Speed: 100Mb/s
 Duplex: Full
 Port: MII
 PHYAD: 32
 Transceiver: internal
 Auto-negotiation: on
 Supports Wake-on: pumbg
 Wake-on: p
 Current message level: 0x00000007 (7)
 Link detected: yes