IP Addresses in the device42 database must be unique per VRF group. So, you can have two subnets with overlapping IP ranges as long as they are in different VRF groups. The only issue with overlapping subnet ranges is that auto-discovery and import will add/modify the IP into first subnet it finds in the list.
IP Address List Page
The list page shows IPv4 and IPv6 addresses that you can sort by any field. You can also filter by type, availability, updated time stamp, subnet and VRF group.
You can search for IPs with full or partial entries right here. Clicking on an IP takes you to the view page.
Bulk actions for IP addresses
The following bulk actions are available for IP addresses:
Delete selected IPs : self explanatory.
Mark selected IP as available: Will only mark those IPs available that have no device and MAC address association.
Mark selected IPs as not available : Will mark selected IPs as not available.
Clear ALL fields and Mark selected IPs as available : This command will clear all device and MAC association for the selected IPs and mark those IPs as available.
Relocate Selected IPs : This will bring up matching subnets page based on first selected IPs. You can choose to move IPs to another subnet with this. Only IPs that are within the range will be moved.
The view IP page shows the details for an IP and you can see the history of changes for that IP from the history button (similar to all other view pages in the application). If you have appropriate permissions, you will see the edit button to edit.
All DNS records that use this IP are shown in the view page as well.
When Adding or editing an IP, the subnet field is required. The application will automatically check if the IP falls within the allowed IP range in the subnet and will not allow duplicate IP to be added in that VRF group or subnet (if not vrf group).
You can choose an existing Device/MAC address or add a new one right from this page.
You can add DNS A/AAAA records for the IP from the Network > DNS Records page and they will be updated on the IP address.
IP address management from the command line
With device42, you can find if an IP is already in d42 instance, suggest next available IP and add an API from the command line using the REST APIs. Here is a post discussing this: https://www.device42.com/blog/2013/03/ip-address-management-from-the-command-line/