Last night I had no sleep. It took me 9 hours of frustration so I"m posting this here to help anyone else who has the problem.
1. I have several sites using WordPress
2. Last night I turned on mod_deflate which compresses files by around 70%, recommended by Google
3. Rebuilt apache.... then couldn't log into any WordPress admin areas.
4. After alot of pain, my last resort was to turn OFF mod_deflate
5. STILL I get errors.
By now I was stressed, very stressed. The server was exactly as compiled before the errors so I emailed my dedicated support guys. Angelo rebuilt apache and all was fine.
I found out what caused the error.
- Angelo compiled apache without suhosin php hardening
- To trace the error I recompiled it again WITH suhosin and the error returned, this proved it was not mod_deflate which caused the error. It was WordPress 3 and suhosin
csf firewall says
Check php for ini_set disabled <<< was not done
Check php for Suhosin
WordPress version 3 has an ini_set in admin.php which tries to change the php memory allocation, and suhosin doesn't allow this = which meant we got a server error on login
I went to Service Configuration >> PHP Configuration Editor >> advanced mode >> Safe Mode disable_functions
and added ini_set
The server error disappears... and security in csf increases
I'll add this to the forum as I didn't find this information anywhere on the internet last night.
It might help others,
By recompiling the server without suhosin my datacentre guy Angelo, highlighted where the problem was. I'd spent 9 hours thinking it was mod_deflate...which was th eobvious culprit as I'd just turned it on.