Subnets failed to scan and SNMP credentials cannot be modified or deleted in IPAM

10/26/2018 5:57 PM

9/13/2023 6:58 AM

This article provides information and steps to resolve the issue when subnets do not scan in manual or automatic modes, and the user is unable to edit or modify SNMP credentials. 

The issue is similar to IPAM scans not running, however the SNMP credentials under IPAM settings cannot be added, modified or changed. 

The IPAMBusinessLayer.log in the server shows the following:

2016-07-19 15:04:51,032 [94] ERROR SolarWinds.IPAM.ScanningEngine.ScanStateManager (null) - Unable to update database with subnet scanner state. Will wait 20 seconds then retry.
System.FormatException: Invalid length for a Base-64 char array or string.
   at System.Convert.FromBase64_Decode(Char* startInputPtr, Int32 inputLength, Byte* startDestPtr, Int32 destLength)
   at System.Convert.FromBase64CharPtr(Char* inputPtr, Int32 inputLength)
   at System.Convert.FromBase64String(String s)
   at SolarWinds.Orion.Security.CryptoHelper.DecryptShort(String encryptedText)
   at SolarWinds.Orion.Security.CryptoHelper.Decrypt(String encryptedText)
   at SolarWinds.IPAM.BusinessObjects.SNMPCred.FromDataReader(IDataReader reader)
   at SolarWinds.IPAM.Storage.DAL.SNMPCredDAL.Get(String SqlPostfix)
   at SolarWinds.IPAM.ScanningEngine.ScanInitializer.CreateSubnetScan(Int32 subnetId, PingSweepDhcpJobSettings& jobsettings, TimeSpan& timeout)
   at SolarWinds.IPAM.ScanningEngine.ScanStateManager.CreateSubnetScanJobSettings(IJobSchedulerHelper scheduler, ScanInstance instance, JobDescription& jobDescription, ScanState& state)
   at SolarWinds.IPAM.ScanningEngine.ScanStateManager.StartJobs(List`1 changeList, List`1 removeList)
   at SolarWinds.IPAM.ScanningEngine.ScanStateManager.Run()

Note this error may not be present.

IP Address Manager

The issue is caused by a problem with the SNMP credentials for IPAM stored in the database. Either the credentials are corrupted or the settings for the credentials are invalid.

Example: A SNMP v1 credential has the AuthMethod and PrivMethod entries you will find for an SNMP v3 configuration.

When the scan attempts to start, it will go to  the database to gather all the SNMP credentials for use during the scan. If that information does not match what it expects or the data is corrupted, the process cannot continue and job faults, causing it to try again and repeat until it is successful.

Note: You must have access to the database, whether from the Orion Database Manager or from the SQL Management Studio. 

1. Stop all services on the Primary poller.
2. Open the database and a new query window.
3. Insert the following query and execute it:

   -- Scripts are not supported under any SolarWinds support program or service.
   -- Scripts are provided AS IS without warranty of any kind. SolarWinds further
   -- disclaims all warranties including, without limitation, any implied warranties
   -- of merchantability or of fitness for a particular purpose. The risk arising
   -- out of the use or performance of the scripts and documentation stays with you.
   -- In no event shall SolarWinds or anyone else involved in the creation,
   -- production, or delivery of the scripts be liable for any damages whatsoever
   -- (including, without limitation, damages for loss of business profits, business
   -- interruption, loss of business information, or other pecuniary loss) arising
   -- out of the use of or inability to use the scripts or documentation.
   
   delete from IPAM_SnmpCred

4. Restart services.

Verify if the scans are now running.

You should now be able to re-insert your SNMP credentials through IPAM Settings > Manage SNMP Credentials.