I have a Comtrend ADSL modem/router that shares a USB printer with IPP.
Windows XP connects correctly, but Windows 7 will not (as is confirmed by many frustrated discussion threads returned by search)
Wireshark shows that when Windows 7 is asked to connect to the printer, it sends:
POST /printers/hp HTTP/1.1 Cache-Control: no-cache Connection: Close Pragma: no-cache Content-Type: application/soap+xml User-Agent: WSDAPI Content-Length: 520 Host: 192.168.1.1:631
This is followed by the XML Probe, and this particular router just closes the connection in response.
Windows XP however sends:
POST /printers/hp HTTP/1.1 Content-Type: application/ipp User-Agent: Internet Print Provider Host: 192.168.1.1:631 Content-Length: 125 Connection: Keep-Alive Cache-Control: no-cache
followed by a query (I'm not familiar with the innards of IPP)
To which the Modem responds:
HTTP/1.1 200 OK
followed by a response that satisfies XP.
Is it is possible to have Windows 7 talk IPP and NOT soap+xml ?
All discussion threads I can find on this have people running around in circles, trying and trying again via the printer install wizard, when it appears that the problem is in the protocol language.