One of my sites has some weird issues that the Plesk control panel locks up quite regularly - having spoken to the hosting support guys they've narrowed to the following code:
Undefined index: HTTP_HOST in /var/www/vhosts/admin.ourwebsite.com/httpdocs/index.php on line xx
This error happens over & over again - the hosting support guys say that there is access from people in Belgium, Singapore & Bangkok within 10 minutes (the site is purely UK based) & that these IP's are attempting to use reverse DNS to find vulnerabilities on the server - he believes the vulnerability is in the php code above - could this be the case?
When we get the problem the 'front-end' of the site is perfectly fine however we cannot get into the MySQL database via Plesk for long periods at a time.
Could anyone suggest any solutions - we run near-similar code on other servers without any of these problems although they use CPanel not Plesk (which I really do dislike)
I hope that seems clear, any advice would be useful - Thanks in advance