Linux Modify SSH telnet Port--server Security Chapter

1. Modify SSH telnet port to 5000

Input Vi/etc/ssh/sshd_config

Port #把 ' #Port 22 ' changed to ' Port '; ( remember to remove the # number before it takes effect )

#AddressFamilyany

#ListenAddress0.0.0.0

#ListenAddress::

Enter the service sshd restart #重启SSH服务;

2. Firewall Add port

By default iptables only a subset of ports, using additional ports such as ' 5000 ' need to add a whitelist in iptables

Vi/etc/sysconfig/iptables

(If no iptables input command

# iptables-p OUTPUT ACCEPT

# Service Iptables Save

)

Join-a input-p tcp-m tcp--dport 5000-j ACCEPT

As follows:

Generated by Iptables-save v1.4.7 on Fri Jul 14 21:19:06 2017

*filter

: INPUT ACCEPT [55:3,250]

-A input-p tcp-m tcp--dport 5000-j ACCEPT <-Join

: FORWARD ACCEPT [0:0]

: OUTPUT ACCEPT [31:2,530]

COMMIT

# completed on Fri Jul 14 21:19:06 2017

Enter service iptables restart

To see if the port is open

/etc/sysconfig/iptables-l-N

3. Security Enhancement Chapter

First, add a user with normal permissions and set the password:

# Useradd Admin

# passwd IMPSW

The server does not allow root login:

# Vi/etc/ssh/sshd_config

#LoginGraceTime2m

#PermitRootLoginno #将 ' Permitrootlogin yes ' instead of ' Permitrootlogin no '

#StrictModesyes

#MaxAuthTries6

#MaxSessions10

# servicesshd Restart #重启SSH服务;

Remote management with the normal user admin login, and then switch to the root user with Suroot to get the highest privileges.

Linux Modify SSH telnet Port--server Security Chapter