IPP printing over Proxy Server.

Hi all,

We're trying to implement IPP printing for some wireless computers.
They are all on a private address space, 10.x.x.x and connect to our
LAN, and the internet via a proxy server. (most ports are blocked)

Our printers exist on our main LAN with real IP addresses. A mac on the
LAN has no problem connecting to the printer, as it just goes direct.

MacOSX however doesn't seem to pass printing traffic through the proxy
when on the wireless, and trys to connect directly to port 631 on
the printer. (Surfing the web and other network applications work
fine, as they route the traffic trough the proxy)

An option of course is to allow traffic through port 631, or create some
routing hacks...

On the other hand, all the windows clients can connect fine to the
printer while on the wireless network - i.e. routes the traffic
through the proxy automatically.

Has anybody else come across this, or can suggest a workaround?

Thanks,

Tim