Determine the autonegotiated ethernet connection speed and duplex using the mii-tool command. Running the following command as superuser with no options will generate basic information about all of the ethernet interfaces on the computer:
[root@server2 ~]# mii-tool
SIOCGMIIREG on eth0 failed: Input/output error eth0: negotiated 100baseTx-FD, link ok
This output shows one interface (eth0) which was autonegotiated to 100 Mbps (100baseTx) and full duplex (FD).
Adding the -v option to the command generates verbose output and will tell you more information about the interface including the manufacturer and model. Type the following command:
[root@server2 ~]# mii-tool -v
SIOCGMIIREG on eth0 failed: Input/output error eth0: negotiated 100baseTx-FD, link ok product info: vendor 00:50:43, model 11 rev 1 basic mode: autonegotiation enabled basic status: autonegotiation complete, link ok capabilities: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD advertising: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control link partner: 100baseT4 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD