09-29-2017 08:03 AM
i cant find an answer quickly in the docs. apologies if I missed it. seems so simple but cannot confirm if I have an error or if I have different use case than most. i figured that basic ICMP scheduled discovery would mark an IP as Used but unmanaged if there was no dns/host record. that seems to work. however I also thought that if we removed that host the next scheduled run would clear the IP and mark it as Unused again such that it would be able to be chosen when allocating a "free" ip. however it doesnt seem like discovery will mark an IP as Unused if it is no longer pingable during the next discovery run. can anyone confirm if that is true? also confirm that when asking for a free IP while creating a host record any IP marked as Used will be skipped, correct?
10-01-2017 07:33 PM
Let's start from the end.
I can confirm you that "Next Available IP" function will bring you only IPs in a "Unused/Free" condition. I've been using this function for day-to-day operations and orchestrations. Never had a problem with that.
About discovery clearing used/unused IPs this is not possible taking in consideration the Infoblox position on the network, specific talking about discovery over ICMP. Even if there is a "predictable behavior" of deleting a managed host object from the database, discovery does not know if the device is not replying ICMP packets due to a real machine decomission or a network restriciton (like a firewall blocking ICMP packets of a endpoint that simply does not respond to a received ICMP packet). I do not even consider this useful because if I receive a support ticket to delete a host object from my IPAM and the related IP address is still alive in the network (for any reason) a unmanaged object will pop-up, alerting the administrator about the device presence over the network.
The "unused" is a start condition for every IP in IPAM database. IPs that reply to ping during discovery will be marked as "used"/unmanaged" and/or will (optionally) be merged with other existing IPAM objects from that same IP. Unused objects will be given as response to "Next Available IP" function.
It is hard to discovery to take decisions because network enviromnents are unpredictable.
Hope this helps,
10-02-2017 05:47 AM