Linux in judgment on network port
Linux use ethtool eth0 to view full-duplex or half-duplex // current full-duplex 
// full full-duplex // half is half-duplex
Check whether the network cable connect the Link detected: yes
exercises
1. First add a new network port 
2. Use the ifconfig -a look at the newly created network port 
3. In the settings can also see the network adapter (eth1) of the MAC address 
4. again active port to
use ifconfig eth1 up or activated using ifup eth1 difference between the two latter is needed to read the configuration file # / etc / sysconfig / network- scripts / configuration file is a network port 
5. Check again ethool eth1 link detected 
complete! !
Added: when the shell landed. It will acquire through reverse DNS host name and IP, so the landing time will be slow
by / etc / ssh / sshd_config modify configuration items useDNS