Задампил трафик
Самое интересно, что запрос и ответ, на которые ругается nginx остаются неизменными в обоих случаях, если верить wireshark:

Прямая связь:
[code]
GET /cgi/web_event.cgi HTTP/1.1

Accept: */*

Host: 192.168.101.20:80

User-Agent: IP Camera Viewer

Connection: keep-alive

Authorization: Basic YWRtaW46



Expires: Mon, 26 Jul 1997 05:00:00 GMT

Cache-Control: no-cache, no-store, must-revalidate

Pragma: no-cache

Content-Type: text/plain



motion_detected_1=off
motion_detected_2=off
motion_detected_3=off
gp_input_1=off
gp_input_2=off
gp_input_3=off
gp_input_4=off
storage_full_smb=off
storage_full_sd=off
storage_full_ftp=off
storage_failure_smb=off
storage_failure_sd=off
storage_failure_ftp=off
in_recording=off
in_snapshooting=off
in_motion_detecting=off
gp_output=off
signal=on
speaker=off
microphone=off
camera_name=DCS-2102
[/code]

Через nginx:
[code]
GET /cgi/web_event.cgi HTTP/1.1

Accept: */*

Host: 192.168.101.29:81

User-Agent: IP Camera Viewer

Connection: keep-alive

Authorization: Basic YWRtaW46



Expires: Mon, 26 Jul 1997 05:00:00 GMT

Cache-Control: no-cache, no-store, must-revalidate

Pragma: no-cache

Content-Type: text/plain



motion_detected_1=off
motion_detected_2=off
motion_detected_3=off
gp_input_1=off
gp_input_2=off
gp_input_3=off
gp_input_4=off
storage_full_smb=off
storage_full_sd=off
storage_full_ftp=off
storage_failure_smb=off
storage_failure_sd=off
storage_failure_ftp=off
in_recording=off
in_snapshooting=off
in_motion_detecting=off
gp_output=off
signal=on
speaker=off
microphone=off
camera_name=DCS-2102
[/code]

А вот то, на что он не ругается, изменяется:

Прямая связь:
[code]
GET /audio/ACAS.cgi HTTP/1.1

Accept: */*

Host: 192.168.101.20:80

User-Agent: IP Camera Viewer

Connection: keep-alive

Authorization: Basic YWRtaW46



HTTP/1.1 200 OK

Expires: Mon, 26 Jul 1997 05:00:00 GMT

Cache-Control: no-cache, no-store, must-revalidate

Pragma: no-cache

Content-Type: audio/ACAS
[/code]

Через nginx:
[code]
GET /audio/ACAS.cgi HTTP/1.1

Accept: */*

Host: 192.168.101.29:81

User-Agent: IP Camera Viewer

Connection: keep-alive

Authorization: Basic YWRtaW46



HTTP/1.1 200 OK

Server: nginx/0.8.38

Date: Tue, 08 Jun 2010 19:30:55 GMT

Content-Type: audio/ACAS

Transfer-Encoding: chunked

Connection: keep-alive

Expires: Mon, 26 Jul 1997 05:00:00 GMT

Cache-Control: no-cache, no-store, must-revalidate

Pragma: no-cache



28
[/code]

И еще вот:

Прямая связь:
[code]
GET /video/mjpg.cgi?profileid=3 HTTP/1.1

Accept: */*

Host: 192.168.101.20:80

User-Agent: IP Camera Viewer

Connection: keep-alive

Authorization: Basic YWRtaW46



HTTP/1.1 200 OK

Expires: Mon, 26 Jul 1997 05:00:00 GMT

Cache-Control: no-cache, no-store, must-revalidate

Pragma: no-cache

Content-Type: multipart/x-mixed-replace;boundary=oxONE_IMAGExo





--oxONE_IMAGExo

x-ts-sec: 1230815733

x-ts-usec: 757810

Content-Type: image/jpeg

Content-Length: 14294
[/code]

Через nginx:
[code]
GET /video/mjpg.cgi?profileid=3 HTTP/1.1

Accept: */*

Host: 192.168.101.29:81

User-Agent: IP Camera Viewer

Connection: keep-alive

Authorization: Basic YWRtaW46



HTTP/1.1 200 OK

Server: nginx/0.8.38

Date: Tue, 08 Jun 2010 19:30:55 GMT

Content-Type: multipart/x-mixed-replace;boundary=oxONE_IMAGExo

Transfer-Encoding: chunked

Connection: keep-alive

Expires: Mon, 26 Jul 1997 05:00:00 GMT

Cache-Control: no-cache, no-store, must-revalidate

Pragma: no-cache



6f



--oxONE_IMAGExo

x-ts-sec: 1230815871

x-ts-usec: 101562

Content-Type: image/jpeg

Content-Length: 14313





5a8
[/code]

Что бы это могло значить?