Unknown general log entry
Saw this in the log just now.
nginx: 2016/03/20 15:22:55 [error] 89386#0: *850 limiting connections by zone "addr", client: 192.168.1.48, server: , request: "GET /filestreamingservice/files/bc6c4a54-f4f6-4f9a-80e1-b1d31bd1e1e8?P1=1458503334&P2=301&P3=2&P4=D0XhXEveNaC%2f4cm%2b4WHp4%2bRe46ZiwWZ5%2f3vy0pOi8dQ%3d HTTP/1.1", host: "tlu.dl.delivery.mp.microsoft.com"
There were a few of them.
Rate limiting of captive portal clients who are making too many requests to the portal. Probably some background process hammering away trying to get to the Internet on a system that isn't authenticated.