Hi I have servers, which needs to connect to microsoft.com with a POST-request: xx,xx.xx.xx NONE/417 4362 POST http://go.microsoft.com/fwlink/? - NONE/- text/html This POST-request will fail (417-error), until I configure "ignore_expect_100 on" in squid.conf (using squid 3.1.6). Are there known problems / issues, with enabling the parameter "ignore_expect_100"? What could be the reason for this 417-error? Is there another way in squid.conf allowing these servers the POST-request? I tried with defining a separate acl (method POST), but this did not worked. The only way, the servers were able to connect to microsoft.com (POST) was with defining the "ignore_expect_100"-option. Thanks a lot. Tom