[200 OK]: A Port80 Software Blog

# re: Does Microsoft ISA Server 2004 support compression?

# re: Really Getting ISA and HTTP Compression to Work Together

# re: ISA 2004 SP2 gets HTTP Compression!!!

So far it has been working fine; however, it does not appear to have site/domain level granularity.

Can HTTPS be compressed?

# re: ISA 2004 SP2 gets HTTP Compression!!!

To answer my own question, it does compress HTTPS too.

It looks as if you can control the compression settings at the IP level.

While it is a step in the right direction, httpZip still provides a bigger bang.

# re: ISA 2004 SP2 gets HTTP Compression!!!

Is this in some connection with:

Event Type: Warning
Event Source: Microsoft ISA Server Web Proxy
Event Category: None
Event ID: 23002
Date: 15.2.2006
Time: 7:51:34
User: N/A
Computer: LJDU
Description:
ISA Server was unable to process a response body from /exchange because the response was compressed by the none method, which is not supported by ISA Server. As a result, the response was discarded. This happens when the server ignores the request from ISA Server for GZIP compression and instead compresses the response with none.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

# re: ISA 2004 SP2 gets HTTP Compression!!!

I originally used ISA 2000 and had compression enabled on our web servers and everything was great. I then upgraded to ISA 2004 and noticed that our web compression was no longer working.

The main problem was that ISA was removing the Accept-Encoding header when it forwarded the request to the web server via Web Publishing. Therefore, the web server didn't know to compress the content, even though it was capable (via IIS built-in compression).

I did some research and at the time, it appeared I was out of luck. So I had written my own HTTP Compression filter that did the compression on ISA. It worked well, but the main drawback was that it is very resource intensive on the ISA Server since all the compression happend on the ISA Server instead of the web server.

After some further research, I found a property named SendAcceptEncodingHeader that you can set on the WebPublishing rule. This allowed the Accept-Encoding header to get to the server and thus the content was compressed.

Now, I installed SP2 over the weekend and realized that my content was no longer being compressed. I knew that SP2 added HTTP Compression support, but I still wanted the compression to happen on the web server and not on ISA.

I opened up the settings and added the following rule: Element: External, Reply With: Enabled, Request For: Enabled.

I also disabled the option "Decompress incoming packets to allow ISA Server Web Filters to inspect the content" under the "Content Inspection" tab.

My web server is now compressing the content and ISA is delivering it. However, I'm not 100% sure that ISA isn't recompressing the content or not. I'm reviewing the performance counter to make sure the CPU % hasn't increased.

So from my intial observation, it appears you can still allow HTTP Compression to pass through to your published web servers.

A nice bonus is that it is now possible for our internal network to send Accept-Encoding headers to external web sites. (Element: Internal, Reply With: Disabled, Request For: Enabled). This will make us good netizens and reduce bandwith on those sites.

Kiliman

# re: ISA 2004 SP2 gets HTTP Compression!!!

I was just reading the post linked above "Really Getting ISA and HTTP Compression to Work Together " about the SendAcceptEncodingHeader.

In the comments, Tom Kagan mentioned an open source HTTP compression filter for ISA. I'm pretty sure he's referring to the one I wrote. I had made it open source and posted it on the ISAServer.org forums.

Small world.

# ISA Compression Round-Up (and Next Steps)

# ISA Compression Round-Up (and Next Steps)

# re: ISA 2004 SP2 gets HTTP Compression!!!

Excellent, Kiliman see this post for more:

http://www.port80software.com/200ok/archive/2006/02/15/1009.aspx

# re: ISA 2004 SP2 gets HTTP Compression!!!

ISA2004 SP2 is a waste of time. I had to roll my server back via a ghost image because SP2 for ISA brang my entire network to a halt.

Routing would not start, it continued to say there was a proxy loop when there was not.

When you upgrade an already working product and it stops working by itself.... You know Microsoft have stuffed something up.

Not very pleased with SP2 for ISA Server 2004.

# re: ISA 2004 SP2 gets HTTP Compression!!!

Great this update :(

Description: Web filter 'DiffServ Filter' is not installed on this server. Install the filter and then restart the Firewall service.

Web filter 'Compression Filter' is not installed on this server. Install the filter and then restart the Firewall service.

Web filter 'Caching Compressed Content Filter' is not installed on this server. Install the filter and then restart the Firewall service.

# re: ISA 2004 SP2 gets HTTP Compression!!!

There are kinks in any release, and Microsoft is no different here with ISA.

Make sure to follow all of their install and config instructions, and we hope that you can get it working on ISA as other posters here have done...

If not, we hope to have a Port80 ISA compression solution released for all this year.

More to come,
Port80

# re: ISA 2004 SP2 gets HTTP Compression!!!

Kiliman

There is a "feature" in ISA SP2 that automatically installs the comression filter...but this causes SendAcceptEncodingHeader metabase setting to no longer work. The workaround you described above to fix the problem is using ISA to compress your web pages...itis NOT using IIS. To fix this problem AND use IIS, instead disable the compression .dll itself completely via ISA. Microsoft support gave me this fix, but hasn't released it publicy yet.

Ian Ippolito

# re: ISA 2004 SP2 gets HTTP Compression!!!

Hey guys, have this problem also with gives me the Event 23002 Source: Microsoft ISA Server Web Proxy. I have the ISA 2004 installed with seervice pack2 but get a lot of those error messages. We have installed a fix because one problem regarding a bug (http://support.microsoft.com/kb/885957/) to KB916106, but since we have installed this fix it begin to give us the erro above described. Do anyone know how to fix this? Do anyone have this problem?

regards

Pedro

# re: ISA 2004 SP2 gets HTTP Compression!!!

Hi,

Are you running Sunbelt - Software IHATESPAM? If so,
found this answer on another forum:

"Sunbelt-Software and I have came up with a solution to this:

On the ISA Server Management Console, Go to: ADD INS and then the WEB FILTERS Tab.

At that point you will find an entry for Compression Filter.

Simply disable that filter and the Cloudmark and Sunbelt-Software will allow downloads and ISA will not reject the response.

Sunbelt-Software has a new product coming out soon that will resolve this issue but this is a viable work-around for now. "

# re: ISA 2004 SP2 gets HTTP Compression!!!

I applied the suggestion and I incapacitated the compression filter.

Question:

When incapacitating this option this can cause myself other problems?

# re: ISA 2004 SP2 gets HTTP Compression!!!

Thank You