Ubuntu configure network commands

Take eth0 as an example

**1.**Configure the network card by DHCP

Edit the file: /etc/network/interfaces:

sudo vi /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 effective:

sudo /etc/init.d/networking restart

Of course, you can also enter the following command directly under the command line to get the address

sudo dhclient eth0

2. Configure a static IP address for the network card

Edit the file: /etc/network/interfaces:

sudo vi /etc/network/interfaces

And replace the line about eth0 with the following line:

The primary network interface,

use Static to find our address

auto eth0
iface eth0 inet static
address 192.168.1.98            
gateway 192.168.1.1             
netmask 255.255.255.0           
network 192.168.1.0
broadcast 192.168.1.255

Use the following command to make the network settings effective:

sudo /etc/init.d/networking restart

**Note: ** After it takes effect, you need to configure DNS before you can go online (step 5)

3. Set the second IP address (virtual IP address)

Edit the file /etc/network/interfaces:

sudo vi /etc/network/interfaces

Add the following line to the file:

auto eth0:1
iface eth0:1 inet static
address 192.168.1.60
netmask 255.255.255.0
network x.x.x.x
broadcast x.x.x.x
gateway x.x.x.x

Fill in all the information such as address, netmask, network, broadcast and gateways according to your situation.

Use the following command to make the network settings effective:

sudo /etc/init.d/networking restart

4. Set the host name (hostname)

Use the following command to view the host name of the current host:

sudo /bin/hostname

Use the following command to set the host name of the current host:

sudo /bin/hostname newname

When the system starts, it will read the name of the host from /etc/hostname.

For more information about setting the host name, please visit here

5. Configure DNS

First, you can add some host names and IP addresses corresponding to these host names in /etc/hosts

To access the DNS server for query, you need to set up the /etc/resolv.conf file.

For example: Suppose the IP address of the DNS server is 192.168.1.1

Edit file: /etc/hosts

sudo vi /etc/hosts

The edit content is as follows:

nameserver 192.168.1.1

Or, edit /etc/resolv.conf and add the following content:

sudo  vi  /etc/resolv.conf

Use the following command to make the network settings effective:

sudo /etc/init.d/networking restart

Ubuntu turn off the firewall

root@ubuntu:/home/homer# ufw status // View status
Status: inactive
root@ubuntu:/home/homer# ufw enable // Turn on the firewall
Firewall is active and enabled on system startup
root@ubuntu:/home/homer# ufw status
Status: active
root@ubuntu:/home/homer# ufw disable // Turn off the firewall
Firewall stopped and disabled on system startup
root@ubuntu:/home/homer# ufw status
Status: inactive

1、 Turn off ubuntu's firewall
 ufw disable
2、 Uninstalled iptables
 apt-get remove iptables
3、 The rest of the commands to turn off the firewall in ubuntu
 iptables -P INPUT ACCEPT
 iptables -P FORWARD ACCEPT
 iptables -P OUTPUT ACCEPT
 iptables -F

CentOS turn off firewall

/etc/init.d/iptables stop

[ root@homeros logs]# /etc/init.d/iptables status // View firewall status
iptables: Firewall is not running.
[ root@homeros logs]# /etc/init.d/iptables start // Turn on the firewall
iptables: Applying firewall rules:                         [  OK  ]
[ root@homeros logs]# /etc/init.d/iptables status
Table: filter
Chain INPUT (policy ACCEPT)
num  target     prot opt source               destination         
1    ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           state RELATED,ESTABLISHED 
2    ACCEPT     icmp --  0.0.0.0/0            0.0.0.0/0           
3    ACCEPT     all  --  0.0.0.0/0            0.0.0.0/0           
4    ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0           state NEW tcp dpt:22 
5    REJECT     all  --  0.0.0.0/0            0.0.0.0/0           reject-with icmp-host-prohibited

Chain FORWARD (policy ACCEPT)
num  target     prot opt source               destination         
1    REJECT     all  --  0.0.0.0/0            0.0.0.0/0           reject-with icmp-host-prohibited 
Chain OUTPUT (policy ACCEPT)
num  target     prot opt source               destination

[ root@homeros logs]# /etc/init.d/iptables stop // Turn off the firewall
iptables: Flushing firewall rules:                         [  OK  ]
iptables: Setting chains to policy ACCEPT: filter          [  OK  ]
iptables: Unloading modules:                               [  OK  ]
[ root@homeros logs]# /etc/init.d/iptables status
iptables: Firewall is not running.

Recommended reference:

Original English: http://www.ubuntugeek.com/ubuntu-networking-configuration-using-command-line.html

Centos permanently turn off the firewall method