Comment 4 for bug 1046292

Jan, principally, your problem only occurs if you try to access the print queue on the Ubuntu 10.04 server using the "ipp" backend on your Ubuntu 12.04 client. One way to work around it is using the "ipp14" backend. The "ipp14" backend is the "ipp" backend of CUPS 1.4.x. With the transitionto CUPS 1.5.x changes on the "ipp" backend have been done for better compliance with the IPP specs. Sinnce then, several IPP printers which are not perfectly IPP-compliant, stopped working with the "ipp" backend. These problems were reported upstream but the bug reports got rejected with the justification that the printers have bugs in their firmware. The new "ipp" backend is absolutely IPP-compliant. Therefore I have introduced the "ipp14" backend so that users can goo back to the still working CUPS-14.x IPP backend if they have one of the buggy printers.

CUPS claims to be absolutely IPP-compliant, and that in all versions, so it is strange why a CUPS server needs the "ipp14" backend on a client. Please report the problem upstream, on http://www.cups.org/str.php. Tell the CUPS versions of client and server there and that the client's original IPP backend has problems to access the server but going back to the IPP backend of CUPS 1.4.x works.