implement test build deploy maintain
continuous integration continuous deployment
network
- gateway:路由器的ip
- subnet: to know whether the other device is inside or outside the LAN:Devices in the LAN(局域网) belong to the same IP address range.掩码
- CIDR Classless Inter-Domain Routing
局域网里的IP，通过交换机。 不是局域网里的 通过路由器
- 任何一个设备为了通信需要三种信息：
- IP address
- Subnet
- Gateway
NAT: Network Address Translation
路由器的重要功能。 private → public. 私有IP地址被路由器的IP地址取代
security;reuse IP addresses;
firewall
allows device IP address at port to be accessed port 的开关 webservers port80
useful command
ifconfig netstat ps aux nslookup ping
CICD
CI:Continuous Intrgration :commit small,frequently.test fast,fix early