Zabbix Agent unable to read /var/log/messages

If you are using the Ubuntu package and didn't change things too much, the running process name should be lighttpd and the default user and group names are both www-data. Check the server.username and server.groupname entries in your config file (/etc/lighttpd/lighttpd.conf) to be certain.

Running ps -fC lighttpd should tell you if it is running and the user id that is is running as. On my system the output looks like

• rik@mary:/home/rik$ ps -fC lighttpd
• UID PID PPID C STIME TTY TIME CMD
• www-data 667 1 0 03:50 ? 00:00:00 /usr/sbin/lighttpd -f /etc/lighttpd/lighttpd.conf

Everything you want displayed under your document-root should be readable by the www-data user and the directories need to be executable by www-data as well. To test this you may want to try using find as the user www-data. The sudo command can help with this. sudo -u www-data find /var/www/sites/mysite.com/http/media/css/ should succeed. If not try again one step up with sudo -u www-data find /var/www/sites/mysite.com/http/media/ and so on until find can return file and directory names. Once there the run the chown and chmod commands against that directory without the -R (recursive) flag. Then test again.

If you are comfortable with all of the files and directories under /var/www/sites/mysite.com/http/media being readable by anyone, you may want to chmod all the files as 644 and the dirs as 755. If you have files that need to have the execute bit set this can be a bit more of a problem unless the all have distinctive extensions. This is done using the -type, -exec, and -name flags like:

1. chown -R id:www-data /var/www/sites/mysite.com/http/media

2. find /var/www/sites/mysite.com/http/media -type d -exec chmod 755 {} \;

3. find /var/www/sites/mysite.com/http/media -type f -exec chmod 644 {} \;

4. find /var/www/sites/mysite.com/http/media -type f -name '*.php' -exec chmod 755 {} \;

   If you don't want lighty to access other files an/or dirs in the tree, you will need to handle things differently. It is always easier if you keep files you want readable in a different directory from those you want kept out of the public eye.

How about current setting of SELinux and iptables on agent box? Can you from agent telnet to server via port 10051?

You can try to check the connectivity between boxes using tcpdump on agent: tcpdump -i your_interface tcp port 10050. Using this you can see the incoming/outgoing packets.