We are using TMG 2010 as web proxy server. The problem is only related to certain search sites. Here are some examples:
http://www.eniro.se
http://www.krak.dk
http://www.degulesider.se
The error message we are getting appears when a search is performed on the site:
- Error Code 64: Host not available
- Background: The gateway or proxy server lost connection to the Web server.
- Date: 2013-02-13 08:39:54 [GMT]
- Server: server.domain.com
- Source: Remote server
I get a failed connection Attempt in the TMG log:
Log type: Web Proxy (Forward)
Status: 64 The specified network name is no longer available.
Rule: Allowed Websites everyone
Source: Internal (ipipipip:57753)
Destination: Internal (80.69.225.152:80)
Request: GET http://www.krak.dk/query=what=all&search_word=test&geo:area=&btn_all=S%C3&B8g
Filter Information: Req ID: 113333b2
Protocol: http
I believe above "Destination" stated as Internal might be a problem?? Seems like these sites build on the same backbone. Since I get the same IP from both sites in the GET. Some sort of load balancing issue maybe?
I read this post: ISA forum thread and ruled out that the registry value "EnablePMTUDiscovery" was involved as it already is enabled (1).
Please give me some advice on this one.
Joakim
