400 bad request errors

[pepejose]

hello again! jeje

well, I've been watching the logs again and the report of Logwatch, now with nginx as reverse proxy in front of apache I have in one hour 441 "NULL 400 Bad Requests" made by  45 ips aprox

example:

17 connections: same ip, same second

IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-"
IP _ - [01/Oct/2009:09:44:40 +0200] "-" 400 0 "-" "-" "-" 

	
These amounts are normal with nginx?
how can I know the causes of this? 	
What can I do?

thanks!! thanks!! thanks!!

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,9695,10431#msg-10431