we use the HTTP compression filter in our ISA 2006 firewall to compress JS and CSS files.
Recently I found out, that the ISA server does not send compressed content to the clients, if the clients sends a "Quality value" for gzip in the "Accept-Encoding" header. If the clients sends a "Quality value", ISA server seems to interpret this as "client
does not support compression". When I monitor the requests, the value for compression/client is set to "No".
I used curl to examine the problem in detail and send different "Accept-Encoding" headers:
- "Accept-Encoding: deflate;q=1.000, gzip;q=0.999, identity;q=0.001" < ISA monitoring: compression/client=No
- "Accept-Encoding: deflate;q=1.000, gzip, identity;q=0.001" < ISA monitoring: compression/client=YES
- "Accept-Encoding: gzip , deflate" < ISA monitoring: compression/client=YES
Summarized: If the client sends a "Quality value" for gzip the ISA 2006 firewall does not return a compressed response.
