NI-3100 DNS LOOKUP FAILURE

fogled@mizzou

I've got an NI-3100 controller that fails DNS lookup. I've double, triple, and quadruple-checked the DNS entries in the controller and the name of the host I'm trying to connect to, they are correct. Another controller in the same building on the same subnet has the exact same settings, and it works OK. But for some reason when I try to use a DNS name to do an IP_Client_Open, I get Error=4:Cannot find host. If I use the IP address instead of the name in IP_Client_Open, the controller connects to the server, but the server rejects the GET request I'm sending because security requires the hostname.

Any ideas? I'm stumped.

fogled@mizzou

BTW I'm currently running Master firmware v3.60.453, and device firmware v1.30.8 on the NI-3100 if that makes any difference.

Joe Hebert

1) Is the gateway setting correct?

2) If you telnet into the master and ping google.com or ping the host name in question, what happens?

3) Are you populating a CHAR array for the host name at run-time? If so, are you sure the array is big enough to hold the entire name?

server rejects the GET request I'm sending because security requires the hostname.

That’s strange. I’ve never heard of anything like that but then again there are a lot of things I haven’t heard of.

fogled@mizzou

Joe Hebert wrote: »

3) Are you populating a CHAR array for the host name at run-time? If so, are you sure the array is big enough to hold the entire name?

Aha! That's it! Never thought to look there. The hostname is kinda long, the container was 2 characters short of the actual hostname length.

Thanks!

Joe Hebert

You're welcome. Glad you found it.

GregG

Also, the hostname you use in the GET request doesn't have to be the same variable that you use for the IP_CLIENT_OPEN address.

In case you needed to communicate to a name-based host at an unpublished DNS name, for some reason.