Cannot connect to GPIB-ENET/1000 from different subnet after network change.

[potterr]

My company uses different subnets for the local network depending on physical location.  For example the GPIB-ENET/1000 is on a subnet for computers near the test area and my desk top computer is on a subnet for our office computers.  I was able to get the GPIB-ENET/1000 working originally by connecting a computer to the test area subnet and using the GPIB Ethernet Wizard to search for devices to detect it and find out its IP address.  I then went to the computer at my desk and ran the GPIB Ethernet Wizard from there, this time using the IP address to detect and install the device.  Everything worked great and I was even able to communicate with the GPIB devices connected to the GPIB-ENET/1000 remotely from my desk. 

I went away on a trip and when I got back I could no longer communicate with the GPIB-ENET/1000 from my desk computer.  I soon learned that our IT department had reconfigured the network.  I power cycled the device so that it would get a new IP address and then used a computer on the test area subnet to find out the new IP address.  I went back to my desk and ran the GPIB Ethernet Wizard with the new IP address but it could not detect the device.  In fact, I cannot ping the device from my desk computer on the office subnet but I can ping it from a computer on the test area subnet.  The computers on the different subnets can ping each other.  The IT department tells me that no ports are blocked between subnets.

I've tried a hard reset.  Static IP as well as DHCP.  I've reloaded the firmware.  The only thing I can see that is really different is the subnet mask went from 255.255.255.0 to 255.255.252.0.  The IP settings are listed below.  Any suggestions would be greatly appreciated.

Cheers,

Rudy

Old (Worked)

IP Address: 132.190.153.143

Subnet Mask: 255.255.255.0

Default Gateway: 132.190.153.1

Primary DNS Server: 132.190.12.39

Secondary DNS Server: 132.190.15.11

New (Doesn’t Work)

IP Address: 10.1.172.30

Subnet Mask: 255.255.252.0

Default Gateway: 10.1.172.1

Primary DNS Server: 132.190.12.39

Secondary DNS Server: 132.190.15.11

[kellis.wiseman]

Hey potterr,

This sounds like such a frustrating issue! While this is probably more of an issue for your IT department, I will help as much as I can.

One difference that I noticed is that the device's new IP address is in the private space, as opposed to the public space which the the old IP address was in. Could you give me the IP address of the computer which you were able to contact in the same subnet as the device? If you could post the IP Settings for your computer as well, that could also help diagnose the problem.

~kgarrett

[potterr]

Hi kgarrett88,

Thank you for your reply.  I’m not sure if the fact that it worked previously gives me hope or just makes me more frustrated.  😛

Computer at Desk (Cannot connect to device)

IP Address: 10.1.216.114

Subnet Mask: 255.255.252.0

Default Gateway: 10.1.216.1

Primary DNS Server: 132.190.12.39

Secondary DNS Server: 132.190.15.11

Computer in Test Area (Can connect to device):

IP Address: 10.1.172.111

Subnet Mask: 255.255.252.0

Default Gateway: 10.1.172.1

Primary DNS Server: 132.190.12.39

Secondary DNS Server: 132.190.15.11

I have been in contact with my IT department.  However due to the fact that I can ping the laptop and not the device, they are thinking it is the device and suggested I contact the manufacturer. 🙂  They can still help out if I come up with anything for them to try.  That is an interesting point you bring up about the old IP being in the public space. 

Thanks!

potterr

[kellis.wiseman]

Hey potterr, 

Let's take a step back and look at the configuration of the device itself- does it have a static IP address, or is it on a DNS server (if it's the latter, you will want to ask your IT department if they can assign the device a static IP address). Assuming it has a static IP address, did you configure it in MAX (Measurement and Automation Explorer) on the computer in the test area? Once you have done that, you need to also set up a new reference in MAX on your desk computer. You do this by right-clicking Devices and Interfaces » Create New » GPIB-ENET/100 » Finish. Then follow the wizard prompts, and when given the option select Specify the name of an already configured GPIB-ENET/100 and enter the IP address for the device.

 Hope this helps. Good luck!

~kgarrett 

[potterr]

Hi kgarrett,

Thank you for the suggestion.  Unfortunately that does not work.  I did as you suggested and I can still only communicate with the device when my computer is on the same subnet as the device.

We put the device on a different subnet, one with a subnet mask of 255.255.255.0 but that did not help.  We still could not communicate with it from a different subnet.  

We moved the device to a different building on a completely different subnet and still cannot talk to it unless we are on the same subnet.

Perhaps it is time to send it back for a replacement...

Cheers

Rudy

[Jackie_B]

Hi Rudy, 

I would suggest referring to the following article which talks about locating and pinging a GPIB device on another subnet:

http://digital.ni.com/public.nsf/allkb/D4A705A42207131186256E84007F3FD3

If you can communicate to this device with a computer on the same subnet, then it is unlikely that there is a problem with the device. I would suggest that your first step be to establish communication by pinging. I would then refer to kgarrett's suggestion to configure it in MAX. 

Good Luck!
Jackie

[potterr]

Hi Jackie,

Thank you for the additional information.  However my device is already set up with a valid IP address.  I can ping it as long as I am on the same subnet.

In the link you provided it says: "It is a good idea to check the IP configuration of the computer the GPIB device is connected to and make sure that the IP address set for the GPIB device resides on the same subnet as that of the computer."

Does this device support Ethernet communication across different subnets?

Once again: I can ping the device from a computer on the same subnet as the device.  I cannot ping the device from computers on different subnets.  Is this just me or is this a known problem?

Thanks,

Rudy

[potterr]

This is the message I get when I try what kgarrett  suggested above.   This worked in January but does not work now.

Image Attached

Rudy

[JasonSmith]

The GPIB-ENET/1000 should work fine across subnets. I just talked to one that was about 5 router hops away, and it responded just fine.

One thing that you could try, is to browse to the IP address in a web browser, instead of going through the GPIB Ethernet Utility. You should see a web page which allows the device to be configured, if your computer can reach it at all. This will help determine if there is something wrong with the GPIB application, or if no applications on your computer can communicate with the device. If you cannot see it in your web browser, could you visit it from a web browser on the local subnet, and confirm that the network settings agree with what you posted in the email earlier? Pay particular attention to the gateway and subnet settings.

Let us know if you learn anything new from this, 

Jason S.

[potterr]

Hi Jason,

It is great to hear that it can work across subnets.  I wonder what is wrong with my device or network…

I can browse to the IP as long as I am on the same subnet, as shown in settings.png.  I cannot brows to the IP when I am on a different subnet, as shown in settings2.png.  No applications (including ping) can communicate with the device when I am on a different subnet.

The IP values listed in settings.png are different from those listed earlier because I moved the device to a lab in the same building as my desk so that I no longer have to walk across the parking lot for testing.  I can communicate with the device from a computer in the lab that is on the same subnet as the device but not from my desk computer which is on a different subnet.

A while back when I was attempting to reset the device I held the reset button in while powering on for longer than the 3 seconds recommended (about 30 seconds) until a red light flashed.  Do you think this could have caused the problem?

Thanks,

Rudy