Daily logs from Logwatch regularly report 400 Bad Request, null: 1744 Time(s) from our nginx logs.
The log entries look like:
18.104.22.168 - - [25/Jan/2011:14:44:19 -0500] "-" 400 173 "-" "-"
Can anyone explain how these are generated and why there are so many? It doesn't appear to be hurting anything, but we've had up to 8000 appear in a day. We host a medium size rails application running on unicorn and nginx.
There is some discussion in the nginx forum, but I haven't found a real solution that decreases the number for 400 Bad Reqeusts logged.