Troubleshooting apache

check httpd service is running or not

• if its not starting the check the syntax of the config file

#httpd -S (display the all files and its location )
#httpd -t  or apachectl configtest
if syntax is ok the config file is correct

• check the error logs of apache
/var/log/httpd/error_log

• apache also requires working dsn client support via /etc/resolv.conf and make sure dns is working fine

• check httpd.conf file there is correct entry of server name is there or not and check the port no
• check the size of the log file if it is full then it ll cause error 500 so make sure that log files are under limit and we can us e tool called logrotate in  /etc/logrorate.d/httpd create configuration file for httpd log files
• It is possible that some other process may be using port 80 or 443. Use netstat command to list open port and their owners:
#nestat -tulpn
#netstat -tulpn |grep ‘:80′
If other process using port 80 / 443, you need to stop them or assign another port to Apache.