1. Linux network related
yum install net-tools
ifconfig view network card ip
ifup ens33 open the network card
ifdown ens33 shuts down the network card
Set virtual network card ens33:0
mii-toll ens33 is the same as ethtool ens33 to check whether the network card is connected
change hostname hostnamectl sethostname davery
DNS configuration file vi /etc/resoly.conf /etc/host file
Temporarily change IP
vim /cat/hosts Edit
Second, firewalld and netfilter
selinux temporarily turns off setenforce 0
selinux shuts down permanently
vi /etc/selinux/config
change SELINUX=disabled
become
The previous version of centos7 used netfilter firewall
centos7 uses firewalld firewall
Turn off firewalld and turn on the netfilter method
systemctl stop firewalld shutdown
systemctl disable firewalld does not allow boot to start
yum install -y iptables-services
Start the iptables firewall service
systemctl enable iptables
systemctl start iptables
iptables -nvL View
Three, netfilter5 table 5 chain introduction
5 tables of netfilter
The filter table is used to filter packets. Common tables include three chains: INPUT, FORWARD, and OUTPUT.
The nat table is used for network address translation and has three chains: PREROUTING, OUTPUT, and POSTROUTING
Fourth, ipstables syntax
View ipstables rules: ipstables -nvL
iptables -F clears the rules
restart rule
service ipstables save saves the current rules to the configuration file
View the configuration file, showing the default rules
ipstables -t filter -t specifies the table
ipstables -Z can clear the counter
[root@davery ~]# iptables -I INPUT -p tcp --dport 80 -j DROP insert
[root@davery ~]# iptables -D INPUT -p tcp --dport 80 -j DROP delete
iptables -nvL --line-numbers
iptables -D INPUT 1
iptables -D INPUT DROP