Can't print to network printer over VPN

Question

Level 1

17 points

Can't print to network printer over VPN

Hi All,

this is weird and subsequently probably easy to solve (I hope):

I have a networked printer in my home network. I also have a (working) PPTP VPN set up to connect to that home network while on the road.

When I open the VPN tunnel, I can adress all devices on the network, including the printer. I can ping it as well as open its Web front end (via Safari).

The only thing that doesn't work is: I can't print over the tunnel!

I've tried turning on "send all traffic over VPN", but that didn't help.

Some research on the web seems to indicate that the solution lies in an option "Exclude Local LAN from Tunnel". This, however, is not an option for the built-in PPTP client in Lion.

Any ideas?

Thank you!

Best regards,

Hans Baumeister

Germany

iMac / MacBook, Mac OS X (10.7)

Posted on Feb 16, 2012 12:01 AM

Reply

Answer 1

Best reply

PAHU

Level 6

16,705 points

Feb 16, 2012 12:15 AM in response to Hans D.

Do you know what protocol is used to connect to the printer? For many consumer printers they use proprietary protocols. So while you can ping and open its internal web page, both of which using standard IP ports and protocols, the printer driver may be wanting to connect on a port that is not available or use a protocol that is not compatible with VPN connections.

Reply

Answer 2

Hans D. Author

Level 1

17 points

Feb 16, 2012 10:05 AM in response to PAHU

Hi PAHU,

good point - it is a Canon MFP.

I presumed that just because it is using CUPS it would talk IP or something, but perhaps it uses something odd.

When I searched about this, I found this article: https://discussions.apple.com/thread/2139243?start=0&tstart=0

It is from you :-)

Do you happen to know if Canon uses a prorprietary protocol? The device is an MF8350.

Thank you!

Best regards,

Hans

Reply

Answer 3

PAHU

Level 6

16,705 points

Feb 16, 2012 2:17 PM in response to Hans D.

Hans D. wrote:

Do you happen to know if Canon uses a prorprietary protocol? The device is an MF8350.

Hello Hans. Yes, the MF8350 uses the Canon proprietary driver - UFR2. This driver can be toublesome with a direct network connection, so not surprised it is giving you trouble with the VPN connection.

Some things to note about the UFR2 driver.

It uses a backend service called UFR2 Backgrounder. This service provides status information about the printer and if it cannot communicate with the printer then it will stop printing
The UFR2 driver redirects the packet transport away from CUPS and uses its own called cntdbmu. The network queue has to be created using LPD but you then see via the print queue URI that the driver changes the queue
The driver uses ports like 41376, 41377, 41380 and 47545

Apart from the above there could be other pecularities about this UFR2 this is impacting your printing. I've never had a need to use VPN with the Mac so I cannot confirm this drivers operation on such, but given all the problems this driver has with just general network printing, I would say that you could have trouble getting this to work reliably.

Reply

Answer 4

Hans D. Author

Level 1

17 points

Feb 16, 2012 10:24 PM in response to PAHU

Hi Pahu,

Thanks for the details - I would agree that the Canon driver is a bit of a mess. I had massive printing issues in Snow Leopard which got worse in Lion. Only very recently did Canon issue an update that seems to be quite stable, at least in the local network.

Quite honestly, while Canon used to be extremely Mac-friendly in the 90's (I used to work in output management), it apparently doesn't give a hoot about Mac users with this product. I've had so many issues with it that I certainly won't buy a Canon device again.

Until then, perhaps the solution lies in attaching it via USB to a print server. On the other hand, I can just wait until I'm back in my home office to print... 😝

Thanks again!

Best regards,

Hans

Reply