server problems - strange apache requests

Question

I have a problem with strange requests comming to my server. Because of these requests my server slowed down very much. In apache log appeared very very much requests like:

78.62.169.xxx - - [25/Apr/2011:20:40:53 +0300] "GET / HTTP/1.1" 500 562 "-" "-"

78.61.236.xxx - - [25/Apr/2011:20:40:53 +0300] "GET / HTTP/1.1" 500 562 "-" "-"

86.100.119.xxx - - [25/Apr/2011:20:40:53 +0300] "GET / HTTP/1.1" 500 562 "-" "-"

Earlier there were no requests, where two last items where "-". If I open error log I can see many errors like:

Request exceeded the limit of 10 internal redirects due to probable configuration error. Use 'LimitInternalRecursion' to increase the limit if necessary. Use 'LogLevel debug' to get a backtrace.

When I set LogLevel debug, in error log appears this information:

[Mon Apr 25 20:59:06 2011] [debug] core.c(3052): [client 77.90.113.xxx] redirected from r->uri = /403.shtml

[Mon Apr 25 20:59:06 2011] [debug] core.c(3052): [client 77.90.113.xxx] redirected from r->uri = /403.shtml

[Mon Apr 25 20:59:06 2011] [debug] core.c(3052): [client 77.90.113.xxx] redirected from r->uri = /403.shtml

Does anybody knows how can I solve it? Can it be DDOS? I think this is not my programming fault, because I haven't changed anything in server that day, when requests started atacking me. Thanks in advance.

Answer 1

Is it the fact that your error pages redirect to something else or you have a mod_rewrite rule that redirects infinitely when an error occurs? to verify it try to access a page that doesn't exist -- that should generate a 404 and see if that has the same problem, because it looks like some error occurs and the webserver is trying to serve the web page for the given error however it ends up redirecting the request in an infinite loop.