I have a bunch of computers in police cruisers running Win7 and they all print over a VPN (RadioIP MultIP) back to their office. The VPN is pretty locked down due to the connections coming over a shared low-bandwidth connection (private radio data system).
All of the clients have an HP m401dne laser printer installed and print fine to it directly over WiFi however over the VPN the print jobs are delayed by many hours, if they ever show up. Sometimes a print job will show up 6+ hours later! All traffic is allowed to the printers IP but SNMP is blocked across the VPN to cut down traffic on the limited bandwidth. the printer shows as online, and the printer status on the laptop will often say "job has been sent to the printer" but the job often never arrives. When the print jobs vanish all other network traffic on the VPN continues to work normally.
Also, other cars can print over the VPN, using the exact same config, to various other model printers, without any delay (the other printers are at different PD's throughout the city).
My question is, has anyone had this, or something similar, occur before? Since the m401dne was installed it is the only printer experiencing the delay. Even the printer that it replaced, plugged into the same LAN cable, with the same IP, didn't experience the delays. I suspect that the printer may be relying on the SNMP traffic to make the print job work but I cant unblock SNMP to test. If you've encountered this before, how did you resolve it?
Thanks!