Query port status command: netstat -an| grep port number
Query service status (whether the service is enabled) command: systemctl status service name
Start the service command: systemctl start service name
Port 21: FTP file transfer service
Port 22: SSH protocol, SCP (file transfer), port number redirection
23/tcp port: TELNET terminal emulation service
Port 25: SMTP simple mail transfer service
Port 53: DNS domain name resolution service
69/udp : TFTP
80/8080/3128/8081/9098 port: HTTP protocol proxy server
110/tcp port: POP3 (E-mail)
119 port: Network
123 port: NTP (Network Time Protocol)
135, 137, 138, 139 ports: LAN-related default ports should be closed.
Port 161: SNMP (Simple Network Management Protocol)
Port 389: LDAP (Lightweight Directory Access Protocol), ILS (Location Service)
443/tcp 443/udp: HTTPS server
Port 465: SMTP (Simple Mail transfer protocol)
Port 873: rsync
Port 1080: SOCKS proxy protocol server common port number, QQ
1158 port: ORACLE EMCTL
1433/tcp/udp port: MS SQL*SERVER database server, MS SQL*SERVER database monitor
Port 1521: Oracle database
Port 2100: Oracle XDB FTP service
Port 3389: WIN2003 remote login
Port 3306: MYSQL database port
Port 5432: postgresql database port
5601 port: kibana
6379 port: Redis database port
8080 port: TCP server default port, JBOSS, TOMCAT, Oracle XDB (XML database)
8081 port: Symantec AV/Filter for MSE
8888 port: Nginx server Port
9000: php-fpm
9080: Webshpere application
9090: webshpere management tool 9200
: Elasticsearch server port
10050: zabbix_server 10050
10051: zabbix_agent
11211: memcache (caching system)
27017: mongoDB database default port
22122 port: fastdfs server default port
Apache release directory: /var/www/html
nginx release directory: /usr/share/nginx/html/
Configure dns file: /etc/resolv.conf
nginx configuration file: /etc/nginx/
Configuration file of yum source: /etc/yum.repos.d/
Apache configuration file: /etc/httpd/conf/httpd.conf
Configuration file for sudo privilege escalation: /etc/sudoers
FTP shared files: /var/ftp
FTP configuration file: /etc/vsftpd/vsftpd.conf
Wind computer configuration domain name analysis file: C:\Windows\System32\drivers\etc\hosts
nfs shared file: /etc/exports
Directory for storing user information used by CentOS: /etc/shadow
Configuration file for log rotation: /etc/rsyslog.conf
Mycat configuration file /usr/local/mycat/conf/
Mysql configuration file /etc/my.cnf
selinux configuration file /etc/selinux/config
It is used to store the mapping relationship between hostname and IP address to resolve the hostname /etc/hosts
Global configuration file /etc/profile
Configure network card information: /etc/sysconfig/network-scripts/ifcfg-ens33 (different virtual machines, file names may be different)
Configure the hostname: /etc/hostname
System main log file: /var/log/messages