ERR_ICAP_FAILURE with ASIHTTPReqeust on Orange France

We have an iOS Application that connects to a WebDav server using the ASIHTTPRequest library - which works very good.

One of our customers has the problem of a 500 status code with an ERR_ICAP_FAILURE message using his mobile provider Orange France. The message seems to be a web cache / squid r开发者_如何学Cesponse to an either incomplete connection/communication or (what I think) a response to the unknown OPTIONS and PROPFIND methods of WebDav.

Our Application has an Android counterpart which seems to work under the same circumstances hence a custom implementation of the connection on the Socket-layer.

What I'd like to know is:

• has anyone experienced a such a response in an somewhat similar setup?
• is this a known problem with ASIHTTPRequest / something I could solve via setting?
• Does Orange France offer an APN not using a proxy

We've seen similar transparent proxies causing similar problems and being a general nuisance before.

There's two ways we've found to work around then:

1. Use https for communication - the proxy then can't get in the way
2. Use a non-standard http port, as the proxys generally only pick up port 80

Option 2 may give you problems on other networks that are firewalled though, so perhaps should only be attempted if port 80 has failed.

It's a bit odd that Android works fine - perhaps it is using a different APN? The iPhone APN settings are likely to be locked down though, so a solution that involves changing to a different APN may not be of much use.