Problem switching SonicWALL Pro 2040 to new IP block

[billyverde]

Hello,

We are running a SonicWALL Pro 2040 Standard with firmware version 3.1.0.7-77s.

I’m running into problems when I try to switch this unit over to a new IP address on a new block (and a new switch) we’ve been assigned. Essentially, when I change the IP address, subnet mask, and default gateway under Network -> Settings all activity on our network ceases. Even stranger is the fact that the two servers already plugged in to this new switch and operating normally on the new IP address block lose Internet connectivity when the SonicWALL unit is plugged in to the switch.

When I change these settings back to those on our old IP block (and on a different switch), everything returns to normal.

I’ve plugged my laptop into the same port on the switch and had no problems connecting to the Internet when I use these exact same network settings, and I’ve verified that there is no IP address conflict on the network.

Restarting and power cycling the SonicWALL unit after moving it to the new switch/IP block does not make a difference.

And I've tried pinging the new default gateway under System -> Diagnostics, and I get a 'timed out' error.

Might there be some security setting or something that I’m missing? The only changes I’m making are the IP address, subnet mask, and default gateway (DNS servers remain the same).

Thanks!

 

[SonicsRule]

Sounds like you have the Servers on public IP's outside the Sonicwall and plugged directly into the Switch.

That being the case the Sonicwall WAN might be ARP'ing for their traffic.

Where the Servers previously behind the Sonicwall?

This is one of those times where you may need to actually post your settings (altered a little) in order to determine the solution.

SR

 

[billyverde]

SR,

Thanks for the response.

Yes, there are a few servers outside the SonicWALL and plugged directly into the new switch. However, they are newer servers, and I don't believe they were ever actually behind the SonicWALL (Just an FYI, we primarily use the SonicWALL as a DHCP server internally. There's another "corporate" firewall farther up the pipe that handles our security. This firewall is out of my hands).

Here are some modified settings...

The SonicWALL has both a WAN and LAN connection, on IP blocks 63.92.xxx.xxx and 192.168.xxx.xxx respectively. Gateway and DNS servers are in the 63.92.xxx.xxx range as well, subnet mask is 255.255.255.0.

There is one file server plugged into the SonicWALL with a public IP in the 63.92.xxx.xxx range as well, and a database server that's only accessible privately via the LAN.

The remaining servers are plugged into the switch outside the SonicWALL unit with addresses in the 208.72.xxx.xxx range.

My ultimate goal is to move both the SonicWALL and the one previously mentioned file server to the 208.72.xxx.xxx IP block.

Hope this helps. Any tips at all would be welcomed.

- B

 

[billyverde]

A little more info... I checked the ARP cache on the SonicWALL unit, and discovered it contains four entries in the 63.92.xxx.xxx range:

- The IP address of the router itself (which presumably changes when I edit it - or does the ARP cache need to be flushed as well?)
- The IP address of the gateway (ditto above).
- Two DNS sever addresses (which I've been told will remain valid - could this be the sticking point?)

Thanks again,

B.

 

[Dinkytoy]

Something that I used to see with the old Sonicwall Pro range is that when I've changed some interface IP addresses I would lose connectivity, similar to what you've stated previously.

Fortunately this first occured when I was playing with an old one outside our live environment a reboot of the device cleared the issue and it then worked as expected. It then repeated when I made the live change, being prepared for it I rebooted and the problem dissapeared.

In short try giving it a restart after the connectivity is lost.

 

[billyverde]

Thanks for all the responses, guys.

Dinkytoy: I've tried rebooting, both by issuing the System -> Restart command from the console and by simply unplugging the device then plugging it in again, but I'm still not regaining connectivity.

I've also tried clearing the ARP cache, both before and after switching to the new IP address, but still no luck.

Any other suggestions? Any questions at all about my current configuration are welcomed, too. I'll answer them the best I can. This is getting incredibly frustrating!

Cheers,

- Billy