19.1 Network Tools
19.1.1 ifconfig
19.1.2 ping 19.1.3 netstat
sudo ifconfig eth0 down/up
sudo ifconfig eth0 192.168.102.123
-a (all) displays all options, default does not display LISTEN related
-t (tcp) only displays tcp related options
-u (udp) only displays udp related options
-n refuses to display aliases, can display all numbers converted into numbers. -l List only services that are in Listen (listening)
-p Display the program name that established the relevant link -r Display routing information, routing table
-e Display extended information, such as uid, etc. -s Statistics are performed by each protocol
-c Execute the netstat command every fixed time.
Tip: The status of LISTEN and LISTENING can only be seen with -a or -l
sudo netstat -anp | grep ftp
19.1.4 Set IP
* Configure the network card by DHCP
220 Chapter 19 Tools
Edit the file /etc/network/interfaces:
and replace the line about eth0 with the following line:
# The primary network interface - use DHCP to find our address
auto eth0
iface eth0 inet dhcp
Use the following command to make the network settings take effect:
sudo /etc/init.d/networking restart
You can also directly enter the following command on the command line to get the address
sudo dhclient eth0
* Configure a static IP address for the network card
(1) Edit the file /etc/network/interfaces:
and replace the line about eth0 with the following line:
# The primary network interface auto eth0
iface eth0 inet static
address 192.168.2.1
gateway 192.168.2.254 netmask 255.255.255.0 #network 192.168.2.0 #broadcast 192.168.2.255
(2) Replace the above ip address and other information with your own. Use the following command to make the network settings take effect:
sudo /etc/init.d/networking restart
3. Set DNS
To access the DNS server for query, you need to set the /etc/resolv.conf file. Assuming that the IP address of the DNS server is 192.168.2.2, then the content of the /etc/resolv.conf file should be:
nameserver 192.168.2.2
Manually restart the network service:
udo /etc/init.d/networking restart
s