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MountainX
Asked: 2011-03-20 19:45:08 +0800 CST

Need help with local network printing while using VPN on Ubuntu 10.10 desktop

  • 772

I can print to my HP printer via the LAN when I'm not connected to the VPN. When connected to the VPN, printing fails.

OpenVPN 2.1.0 x86_64-pc-linux-gnu [SSL] [LZO2] [EPOLL] [PKCS11] [MH] [PF_INET6] [eurephia] built on Jul 12 2010

I can ping the printer while connected to the VPN:

$ ping 192.168.100.12
PING 192.168.100.12 (192.168.100.12) 56(84) bytes of data.
64 bytes from 192.168.100.12: icmp_req=1 ttl=255 time=9.17 ms
--- 192.168.100.12 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss...

$ ping HpPrinter.local
PING HpPrinter.local (192.168.100.12) 56(84) bytes of data.
64 bytes from HpPrinter.local (192.168.100.12): icmp_req=1 ttl=255 time=0.383 ms

--- HpPrinter.local ping statistics ---
4 packets transmitted, 4 received, 0% packet loss...

But here's the error when I try to print while connected to the VPN:

hpijs[9990]: io/hpmud/jd.c 784: mdns lookup HpPrinter.local retry 1...
...
hpijs[9990]: io/hpmud/jd.c 784: mdns lookup HpPrinter.local retry 20...
hpijs[9990]: io/hpmud/jd.c 780: error timeout mdns lookup HpPrinter.local
hpijs[9990]: io/hpmud/jd.c 88: unable to read device-id
hp[9982]: io/hpmud/jd.c 784: mdns lookup HpPrinter.local retry 1...
...
hp[9982]: io/hpmud/jd.c 784: mdns lookup HpPrinter.local retry 20...
hp[9982]: io/hpmud/jd.c 780: error timeout mdns lookup HpPrinter.local
hp[9982]: io/hpmud/jd.c 88: unable to read device-id
hp[9982]: prnt/backend/hp.c 745: ERROR: open device failed stat=12: hp:/net/Officejet_Pro_L7600?zc=HpPrinter

I am running iptables rules, but the problem doesn't appear related to the firewall. I've tested with no rules (i.e., no firewall). The printing problem happens when the VPN is connected. I can guess it is an mdns problem, but searching google about mdns didn't turn up anything that seemed related to this (at my level of knowledge). Any suggestions?

linux ubuntu printing openvpn local-area-network

2 Answers

  1. Best Answer

    I had a bit of dumb luck... I had been looking for "proper" solutions (and trying to learn more about what is causing the issue) and then for some reason I suddenly thought to try System > Administration > Printing. The GUI showed my printer at:

    Original location: hp:/net/Officejet_Pro_L7600?zc=HpPrinter

    I used the GUI wizard to find the printer again, this time while using the VPN. It came up with this location: dnssd://Officejet%20Pro%20L7600%20%5B32C801%5D._pdl-datastream._tcp.local/

    Now printing works while on the VPN.

    WHY??? I would really like to know what all this means as well as what the security implications are of mdns. I would appreciate any comments anyone wants to add.

    • 0

  2. In my Anyconnect client, I can click on the gears icon to edit "settings" and then select "Allow local (LAN) access when using VPN (if configured)". When I check that box and reconnect to the VPN, I can access my (local) network printer and other resources.

    • -1