how exactly IPAM detect IP conflict on network?

How does IPAM detect conflicts?

IPAM primarily looks for differences in MAC addresses, from two distinct simultaneous scans for a single IP Address, within a subnet.

Conflict Scenarios:

SNMP versus SNMP Neighbor: This type of conflict will occur when there is a difference in MAC addresses retrieved from the ARP table of the configured device and SNMP OIDs during the subnet scan for a particular IP Address.

SNMP versus DHCP: This type of conflict will occur when there is a difference in MAC fetched from SNMP OID and DHCP leases from DHCP Server, for a particular IP Address during a subnet scan.

SNMP Neighbor versus DHCP: This type of conflict will occur when there is a difference in MAC addresses retrieved from ARP table of the configured device and DHCP leases from DHCP Server, for a particular IP Address during subnet scan.

DHCP versus DHCP: A range of IP Addresses within a subnet may be managed by two DHCP servers. This type of conflict will occur when there is a difference in MAC addresses retrieved from two DHCP servers lease information for a particular IP Address during subnet scans.

DHCP versus DHCP (Scope Overlap): A range of IP Addresses under a subnet may be managed by two DHCP servers. There are cases wherein a part of an IP Address range under one DHCP server would be managed by another DHCP

server. In both instances, there is an overlap in scopes between two DHCP servers. This is considered a conflict

IPAM reservation versus SNMP/DHCP/SNMP neighbor: There are situations where you reserve an IP Address under a subnet in IPAM that contains a MAC address for an internal reference. This type of conflict will occur when there is a difference in MAC addressees from either SNMP OIDs, or DHCP leases, or neighbor devices with reserved MAC addresses in IPAM , for a particular IP Address during a subnet scan.

Note: l IP conflict occurs from a MAC comparison between snmp > ARP, snmp > snmp (rare), ARP > ARP, snmp > DHCP, ARP > DHCP. IPAM detects conflicts through the following:

- If there is no DHCP server in your environment that IPAM is scanning, then two machines need to both support SNMP polls so that IPAM

sees the MAC address on both devices.

- If IPAM, during a scan, discovers two machines MAC address with identical IP, IPAM generates an event noting this discovery. 

During subnet scans, MAC addresses obtained from SNMP, SNMP neighbor, and IPAM reservations are termed as Static entries and those

obtained from DHCP servers are termed as Dynamic entries.

@donrobert5  so one way to detect IP conflict is the VMs or devices must be add via SNMP to solarwind. i try to test this scenario.
i add two linux node each with two NIC to solarwinds by SNMP. solarwinds detect NIC names IP and MAC addresses. as shown in below. i wait 1h for sure. no warning or event generate. i manually trigger subnet scan and wait 20min. the only event i fount was 
"The scanning of '172.16.144.0 /24' started at 4/9/2024 11:42:52 PM has finished successfully. 107 IP(s) were found. The scan duration was '1.2' minutes."
so in this scenario how ip conflict detection work or what i missed?

What you are showing here are interface details not IP Address Details.  Can you show me what is being showed via IP address Details?

this is IP address details for 172.16.144.222

this is IP address details for 172.16.144.222

It doesn't seem to detect association with MAC addresses at all.  What you need to understand is that whatever it detects via the Interface Details does not translate directly to IPAM.  It has it's own Polling therefore you will need to check if the SNMP Credentials via Manage Nodes is included on the IPAM as well.

i add new SNMP community to IPAM polling via solarwinds.setting\IPAM setting\SNMP credential. scan the range manually and the information has been fetch. both linux node has the same SNMP credential.

Ok, then that means it is only associating on one MAC address when it Queries the IP Address VIA SNMP.  As you can see on the scenario,  there's no SNMP Vs SNMP because it usually gets one association.  You will need to check the other ones like adding a DHCP server to get the other association and detect the IP Address Conflict or it can also be SNMP VS, SNMP Neighbor.

Here's a document to know more about neighbor scanning.

documentation.solarwinds.com/.../ipam-neighbor-scanning.htm

so as we know, SOLARWINDS knows that one IP address is assign to more than one MAC address (when i add nodes via SNMP, the information about NIC and MAC is already in DB).but there is no SNMP vs SNMP.. so can i ask for this feature be add in future IPAM release?

You are comparing the IPAM Module and the NPM.  Your question is about how IPAM detects IP Conflict.  The information you are referring is not native to IPAM though.  But feel free to request a Feature Request.

www.solarwinds.com/.../how-to-submit-a-product-feature-request

 now i understand that IPAM module is semi-independent from NPM. the scenario we reviewed is a valid case at least for me. according to this test, IPAM conflict detection method will not compare ARP table of two UDT or SNMP neighbor devices as well, right ?
  

IPAM can get the ARP table values via Neighbor scanning which is I provided a link above.