Printing through SonicWall VPN

Dennis Janson
Dennis Janson used Ask the Experts™
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I had setup a site-to-site VPN connection with two SonicWall routers. I was able to print to a network printer on the other LAN. Today the site with the Printer had a power outage, now I can log into the Router remotely but cannot ping or access any devices on that LAN. I rebooted all routers and went through all the Firewall rules and everything looks normal. Any ideas?
The Printer in set to DHCP and the settings are correct.
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If you can access the remote Sonicwall via the Lan ip address it would mean the VPN tunnel between both Sonicwalls is OK. You say there was a power cut on the remote site.
Check the DHCP assigned address of the Printer if the address is correct is the default gateway and the DHCP server address. Is the Sonicwall or a server giving out the DHCP addresses. The re-start may have activated a DHCP server that is not setup correctly.
Dennis JansonIT Manager

Author

Commented:
The I cycled the power on the printer after restarting both VPN routers. The IP, DG and DHCP settings on the printer are correct and match the settings on the router. The local router is the DHCP server. Here is the quick view of the setup.

Printer (IP 10.0.3.206,DG 10.0.3.1)

Router at remote site (10.0.3.1, DHCP range 10.0.3.3 - 10.0.3.255)

Internet------

Router local site (IP 10.0.0.2)
DNS Server (10.0.0.1)
My IP static (10.0.0.22)
My Network Printer (10.0.0.31)


From a PC on the remote site I can get web access to my printer (10.0.0.31), but from my PC I cannot access the remote printer (10.0.3.206)
Can you ping the remote printer from the remote Sonicwall if you can it means the internal network is ok ie default gateway hub etc.
If you can ping 10.0.3.1 from you PC there is no reason not to get access to the printer, unless there is a problem with the hub/switch or the ip configuration.
One other possibilty is there an entry in the routing section of the firewall that should not be there.
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Dennis JansonIT Manager

Author

Commented:
Exactly. I cannot ping the remote printer from my PC, nor can I ping it from my local router. Though I can do the reverse from a PC on the remote LAN. I have been trying to find a blocking issue with either firewalls but I had set a fire wall rule on each router for testing that opened up all ports for access.
Can you ping the remote Sonicwall Lan ip 10.0.3.x from your PC
Dennis JansonIT Manager

Author

Commented:
Yes. I can ping and also log into the SonicWall at 10.0.3.1
When you logon to the remote Sonicwall (10.0.3.1) can you ping the printer (10.0.3.206) from the Sonicwall. If that works check the destination networks under the netwok tab in the VPN config section. It should be the network of the remote site.
Your local sonicwall should list a network 10.0.3.0 255.255.255.0
The remote sonicwall should list a network 10.0.0.0 255.255.255.0.
IT Manager
Commented:
That is exactly how I have it setup. It originally worked.  But without changing a thing, to my surprise, I can magically access the printer through the web. Imagine that! And people say computers have no personality.
When you attempt to print to the remote printer, check the filewall logs on both Sonicwalls you should see one of them dropping or blocking traffic on port 9100 if the printer is setup with standard IP ports.
Dennis JansonIT Manager

Author

Commented:
Explain this. I have done absolutely nothing to our system, but I now cannot access the printer again.
If your PC did not get a reply it may have cached the failed result. When this happens use ipconfig /flushdns to clear the DNS cache on the PC and try the ping again.
Dennis JansonIT Manager

Author

Commented:
I have tried flushing the DNS. The ability to reach this printer or not seems to be random at best. I'm thinking it maybe a time out issue. Last time I was able to access I did install the printer on my machine. It is currently in the "ready" state but cannot send a print job to it.
Is the bandwidth being used by another process when the access to the printer is not available.
Is netbios traffic being routed over the VPN link. When the printer is not available can you connect to other resources on the remote network. Are either of the links being used Email or FTP upload / download.
Dennis JansonIT Manager

Author

Commented:
The remote network only consist of one printer and one PC. I cannot ping either when it is not availible.
 I turned on netbios on the VPN settings and it did not make a difference.
 I am not using the links for FTP or email.
I would recomend disabling the Netbios traffic. When the printer is not available can you connect to the remote Sonicwall, is any traffic crossing the VPN link.
What broadband links are you using ie ADSL 8mb down 0.5mb up ?
If the links are DSL you should change the MTU setting to 1404 on the Wan Link on Both Sonicwalls.
The MTU setting is in interface > advanced.
Dennis JansonIT Manager

Author

Commented:
I disabled the Netbios traffic back to default.
I can always access the remote SonicWall. There is no other traffic over this VPN connection.
The remote location has ADSL and I adjusted for the MTU packets to 1404 as you stated. Still no change yet on accessing the printer.
Is there a hub / switch on the remote site, could it be faulty or overheating.
From what you have said when the printer is not available you can connect to the remote Sonicwall, but you are not able to ping the printer from the remote Sonicwall. Which implies the VPN link is fine but the problem is the internal network on the remote site.
If there is a hub / switch can it be replaced or use the network ports on the Sonicwall if they are available.
Dennis JansonIT Manager

Author

Commented:
I can ping the printer from the remote firewall.
Is there a hub / switch on the remote site
Dennis JansonIT Manager

Author

Commented:
Yes, there is a 5 port Netgear (Walmart Special) hub. The PC is connected through it to with no problems.

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