Some necessary processing work after installation of CentOS

1 Permanently close SELinux, modify to permissive or disabled (recommended), modify the need to restart

2 Configuring Network

3. Disable ping (optional, generally do not need to prohibit) (default is 0-bit enable ICMP protocol, 1 is forbidden), no restart required after modification

1. [[email protected] ipv4]# echo "1" >/proc/sys/net/ipv4/icmp_echo_ignore_all

Or add a sysctl.conf in the

1. [Email protected] ~]# echo "net.ipv4.icmp_echo_ignore_all=1" >>/etc/sysctl.conf
2. [Email protected] ~]# tail-1/etc/sysctl.conf
3. Net.ipv4.icmp_echo_ignore_all=1
4. [Email protected] ~]# sysctl-p

(optional) Display the message after logging in, enter the information that needs to be displayed after login

1. [Email protected] ~]# echo "It is product Environment,be careful ..." >/ETC/MOTD

5. Modify the default SSH settings to increase system security
Backing Up Sshd_config files

[email protected] ssh]# cp/etc/ssh/sshd_config/etc/ssh/sshd_config.bak.20150915

Modify the following configuration

1. //Modify the default port    for SSH remote connection;
2. #Port  22  
3. Modify to   
4. port 2510 port number to specify   
5.    
6. //ssh does not allow root user login   
7. #PermitRootLogin  yes  
8. Modify to   
9. PERMITROOTLOGIN NO  
10.   
11. //resolves the problem of slow DNS resolution   
12. #UseDNS  yes  
13. modified to   
14. usedns no  
15.   
16. //Resolve ssh slow problem   
17. #GSSAPIAuthentication  no  
18. gssapiauthentication yes  
19. Modify to   
20. gssapiauthentication no  
21. #GSSAPIAuthentication  yes  

6. Optimized terminal timeout, automatic disconnection of terminal over 600 seconds

• [Email protected] ~]# echo "Export tmout=600" >>/etc/profile

1. [Email protected] ~]# tail-1/etc/profile
2. Export tmout=600
3. [Email protected] ~]# Source/etc/profile

7. Control History Command record number, History command file path: ~/.bash_history

1. [Email protected] ~]# echo "Export histsize=20" >>/etc/profile
2. [Email protected] ~]# echo "Export histfilesize=20" >>/etc/profile
3. [Email protected] ~]# Tail-2/etc/profile
4. Export HISTSIZE=20
5. Export HISTFILESIZE=20
6. [Email protected] ~]# Source/etc/profile

Some necessary processing work after installation of CentOS