1. The direction of software problem analysis
a. Business direction
b. Technical direction
Find problems, analyze problems, and propose solutions
2. Line
user-level problems -> Web page/software interface -> Middleware -> Back-end service -> Code- > Database
3. Examples of problems
. When I visit a web site deployed on a Linux system through a Windows browser, I find that the site cannot be accessed. How to analyze and locate the problem?
a. Open the network if other sites can normally access
b. server can ping the IP address of
c. server monitor tcpdump -v port 80 (the exact site port)
in a client visit the site to view the server listening situations
d. View the server side Firewall status
service iptables status
Start the firewall: service iptables start
Close the firewall: service iptables stop
can not simply and rudely turn off the firewall, it can be customized, the firewall is open but allows access to certain ports, such as allowing access to port 80
iptables -I INPUT -p tcp --dport 80 -j ACCEPT
This command can always take effect after adding the firewall configuration file