In Linux, you can set up uninterrupted running of iptables.

# Check whether the iptables command is/sbin/iptables [root @ test ~] # Whereisiptablesiptables:/sbin/iptables/usr/share/man/man8/iptables.8.gz # iptables has several default table tables, including filter, nat, and mangle # Initialize fil

# ConfirmIptablesWhether the command is/sbin/Iptables

[Root @ test ~] # Whereisiptables
Iptables:/sbin/iptables/usr/share/man/man8/iptables.8.gz

# Iptables has several default table tables, including filter, nat, and mangle.

# Initialize the INPUT, OUTPUT, and FORWARD chains of the filter table.

[Root @ test ~] #/Sbin/iptables-P INPUTACCEPT
[Root @ test ~] #/Sbin/iptables-P OUTPUT ACCEPT
[Root @ test ~] #/Sbin/iptables-P FORWARD ACCEPT

# Initialize nat tables PREROUTING, POSTROUTING, and OUTPUT chain to allow

[Root @ test ~] #/Sbin/iptables-t nat-P PREROUTING ACCEPT

[Root @ test ~] #/Sbin/iptables-t nat-P POSTROUTING ACCEPT

[Root @ test ~] #/Sbin/iptables-t nat-P OUTPUT ACCEPT

# Initialize the mangle table PREROUTING, INPUT, FORWARD, OUTPUT, and POSTROUTING chain to allow

[Root @ test ~] #/Sbin/iptables-t mangle-P PREROUTING ACCEPT

[Root @ test ~] #/Sbin/iptables-t mangle-P INPUT ACCEPT

[Root @ test ~] #/Sbin/iptables-t mangle-P FORWARD ACCEPT

[Root @ test ~] #/Sbin/iptables-t mangle-P OUTPUT ACCEPT

[Root @ test ~] #/Sbin/iptables-t mangle-P POSTROUTINGACCEPT

# Clear all filter rules & Custom Tables & traffic clearing
[Root @ test ~] #/Sbin/iptables-F
[Root @ test ~] #/Sbin/iptables? Z
[Root @ test ~] #/Sbin/iptables-X

# Clear all nat rules & Custom Tables & clear traffic
[Root @ test ~] #/Sbin/iptables-t nat-F
[Root @ test ~] #/Sbin/iptables-t nat? Z
[Root @ test ~] #/Sbin/iptables-t nat-X

# Clear all mangle rules & Custom Tables & traffic clearing

[Root @ test ~] #/Sbin/iptables-t mangle-F

[Root @ test ~] #/Sbin/iptables-t mangle? Z

[Root @ test ~] #/Sbin/iptables-t mangle-X

# Allow data similar to sending back. if this rule is not set, connection speed similar to ssh application is slow.
[Root @ test ~] #/Sbin/iptables-a input-m state -- stateESTABLISHED, RELATED-jACCEPT

# Allow all connections to the circular network card

[Root @ test ~] #/Sbin/iptables-a input-I lo-jACCEPT
# Allow port 22 connection

[Root @ test ~] #/Sbin/iptables-a input-p tcp -- dport 22-jACCEPT

# Allow ping

[Root @ test ~] #/Sbin/iptables-a input-p icmp -- icmp-type 8-jACCEPT
# The input chain is set to drop by default.

[Root @ test ~] #/Sbin/iptables-P INPUT DROP

# When using a remote host, open an ssh connection to check whether the connection is normal.

# Normally, you can connect to the server. if not, contact the administrator to restart the server.

# Save the configuration to the hard disk

/Etc/init. d/iptables save

# Viewing IP status