Solarwinds IPAM - how to check ping scan and DNS being used by IPAM - hosts not being marked as in use.

Check what Polling engine the subnet is assigned to and then logged into that APE.  try to do ping -a XX.XX.XX.XX and see if it will respond and resolve the IP Address to hostname.

https://support.solarwinds.com/SuccessCenter/s/article/How-hostname-resolution-works-in-IPAM

I have checked the assigned Solarwinds poller and logged into the poller host.   I can ping from the poller to the host that I am expecting to be marked as in use.  It pings as below.  However it is shown in IPAM as available (not correct).  Is solarwinds IPAM not configured properly.  Pinging unitysql-t2.staff.uce.ac.uk [10.255.50.21] with 32 bytes of data:
Reply from 10.255.50.21: bytes=32 time<1ms TTL=127

PS C:\Users\IDadm> $myhost = [System.Net.Dns]::GetHostEntry("10.255.50.21")
PS C:\Users\IDadm> $myhost

HostName                    Aliases AddressList
--------                    ------- -----------
unitysql-t2.staff.uce.ac.uk {}      {10.255.50.21}

check if you also enabled the neighbor scanning for the subnet.  If it is, disable it and verify again that you are checking the Poller assignment from the subnet and not via Node.

Point of clarification on this thread, IPAM doesn't consider if your DNS server has a record as a way to verify if an IP is available or not it only gets status through DHCP (there being a lease time), Neighbor Scanning or ICMP sweeps. Your ping seems to target the Hostname see if when you Ping the IP does it return a result, if not then IPAM is working as expected. 

Thanks for you advice on Pollers, the primary polling engine was not pingable - think there is a tunnel.  You can ping it from additional poller.  I have used additional poller.  Starting to get sone IP addresses I expected showing as in use.   I did not know about the DNS relation - how that info is used.  I thought if you have A record then it could infer that address is not available.  When I did ping the end host from the APE, it was to IP address and it resolved the dns name.  Does this mean ICMP scanning is working since at least one subnet has shown results.

Yeah the scanning overall is working, you may have other issues pending on how the subnets are setup or if the IP's aren't reachable from a particular Poller. Its just a matter of if something doesn't look right start checking through the process to figure it out. I typically would do the below to verify.

1. Try to ping the IP from the polling engine the subnet is assigned too.

2. Check if there is a DHCP lease for the IP.

3. Check if it shows up in Neighbor Scanning Data (if enabled) https://documentation.solarwinds.com/en/success_center/ipam/content/ipam-neighbor-scanning.htm

If all that checks out and IPAM doesn't match what your expected results are at that point I'd look at opening a support ticket or check out the success center for more specific info.

Yeah the scanning overall is working, you may have other issues pending on how the subnets are setup or if the IP's aren't reachable from a particular Poller. Its just a matter of if something doesn't look right start checking through the process to figure it out. I typically would do the below to verify.

1. Try to ping the IP from the polling engine the subnet is assigned too.

2. Check if there is a DHCP lease for the IP.

3. Check if it shows up in Neighbor Scanning Data (if enabled) https://documentation.solarwinds.com/en/success_center/ipam/content/ipam-neighbor-scanning.htm

If all that checks out and IPAM doesn't match what your expected results are at that point I'd look at opening a support ticket or check out the success center for more specific info.