Devices showing unreachable in LMS 4.2

Question

Hi ,
I have discovered my switches in LMS but it is showing unreachable what can be the reason ?
Looking forward for your comments .
thanks in advance,
Pandian G K

Answer 1

I also have hundreds of unreachable devices found by CDP and the only report that has any data is the one that's created when clicking on the number of unreachable devices in the summary screen. There is no data when I go to Reports>Inventory>Management Status>Unreachable Devices while the discovery is running.
From everything I have read this means that SNMP is not responding to RO requests but this seems quite inadequate based on the fact that these are found with CDP. I could understand only providing a IP addresses for an unreachable device discovered with a ping sweep but CDP gives a huge mount of information about a connected device and all LMS returns is an IP address and its neighbors.
Is there anyway to get more detailed information about the unreachable devices without turning on debug and running the discovery again? We are discovering thousands of devices and it's taken 4 days so far so starting over is not really an option based on the timeframe we have for this project.
I will try to see if the log files show any useful information but I have a feeling that trying to do this for hundreds of devices will not be a good use of time and the advice to just telnet or SSH to each device to validate their credentials will also take a huge amount of time as we could easily have over a thousand unreachable devices by the time the discovery is finished.
Also, DCR verification is only for devices that end up in the DCR, which unreachable devices do not and none of the discovery reports seem to have any data until the discovery is complete so trying to get this info during a large discovery has proven difficult at best. Any advice would be very much appreciated.