topic Re: HTTP Head Keepalive and IIS 6.0 in Application Networking

HTTP Head Keepalive and IIS 6.0

plearmouth — Tue, 05 Jul 2005 16:47:12 GMT

Hi,

The document

"Making Cisco CSS 11000 HTTP Keepalives and ColdFusion Servers Work Together"

implies that the CSS requires a response '200 OK' and a content-length header as well for a persistent connection.

It would appear that IIS 6.0 simply does a connection:close as some sort primitive method of suggesting the length, that is NO content-length header.

Either way the service keepalives stay down. I have not tried non-persistent connections.

I also found a bug fix that suggests that a 200 OK with no headers is sufficient for a KA.

The customer has 11506's so is the document still valid ?

Thanks in advance

Paul

Re: HTTP Head Keepalive and IIS 6.0

Gilles Dufour — Tue, 05 Jul 2005 17:34:27 GMT

Paul,

With the method HEAD, the server is not supposed to return any data, just the header.

So if the header does not contain a 'content-length' the client/CSS has no way to know what is the data length.

Anyway, normally the CSS only check the response code. Are you certain the server returns 200ok ?

what's your software version ?

I think there was also another bug related to server closing the connection having a negative effect on keepalive.

I would suggest to try the latest version first and if the problem persist open a TAC case.

Regards,

Gilles.

Re: HTTP Head Keepalive and IIS 6.0

plearmouth — Tue, 05 Jul 2005 17:56:55 GMT

Giles

Thanks for your quick reply.

Below is a ethereal trace of the response (with a browser initiated GET to the URI in question).

This is all I have at the moment but it shows that for the GET ( HEAD should be the same) there is no

content-length header.

Ethernet II, Src: 00:0f:23:ec:1e:00, Dst: 00:0f:1f:71:a7:cf

Internet Protocol, Src Addr: 10.58.32.60 (10.58.32.60), Dst Addr: 10.60.32.84 (10.60.32.84)

Transmission Control Protocol, Src Port: 81 (81), Dst Port: 8196 (8196), Seq: 1, Ack: 545, Len: 239

Hypertext Transfer Protocol

HTTP/1.1 200 OK\r\n

Response Code: 200

Connection: close\r\n

Date: Thu, 30 Jun 2005 09:53:35 GMT\r\n

Server: Microsoft-IIS/6.0\r\n

Content-Type: text/html; charset=utf-8\r\n

Expires: 0\r\n

Pragma: no-cache\r\n

Cache-Control: no-store\r\n

Set-cookie: ~http_content_charset=utf-8\r\n

\r\n

So is it required ?

Regards

Paul

Re: HTTP Head Keepalive and IIS 6.0

Gilles Dufour — Tue, 05 Jul 2005 18:13:54 GMT

As I said, the CSS normally does not need the content-length.

That's why I asked you about the version you are running.

Also, I would capture a sniffer trace of CSS keepalive using HEAD which can have different result.

Thanks,

Gilles.

Re: HTTP Head Keepalive and IIS 6.0

plearmouth — Mon, 11 Jul 2005 09:06:04 GMT

Giles,

Used Telnet to confirm your suspicions,the response from the HEAD method was 500. Confused how you make a website

respond with a successfull GET method but then a 500 for the HEAD, I thought the purpose of HEAD was too allow the browser to check the properies of the content without actually retrieving it.

So, using the script AP-KAL-HTTPCHECK ( search a web page to locate a substring). Is there a way to pass a parameter like 'R/3 Status OK' as one entitiy, the parser seems to want to treat it as three seperate pieces.

I have hardcoded into the script to make it work.

Thanks in advance

Paul