What version of SNMP you are using on these 26 devices ?Try to do the following:
- Go to Device Center
- Select one device for test
- click on "check device credentials", select SNMP according to the version you are using.
- See the results.
May be you get more technical and detailed information about the SNMP timeout error. I have already experienced some problems using SNMP v3. The problem was resolved when I configured the SNMP v2c instead of v3.
Also, I suggest you to try do "SNMP walk" test in the Device Center. If you get some results reading, for example, the value of "sysObjectId", just verify the Credentials Settings in DCR. You can edit the Credentials trhough the Device Center -> Edit device credentials.
I suggest you to do a "SNMP walk" test (through Device Center), trying to get the value of the "sysObjectId" and enable the "debug snmp" on the device console. So, through the device terminal, you will see if the device is reacheable by SNMP and why it is not responding to the DFM.
By the way, are these devices supported by DFM? What device model we are talking about? What is the IOS version?
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...