Check the setting in your Agent Configuration. Under Standard LANDesk Agent/Inventory Scanner there is an option to do a scan whenever the IP address changes. You can also schedule scans to run on a regular interval.
Kurt is right - this is an agent configuration setting. What version of LANDesk are you using?
Your configuration should at least have Miniscan on IP change set and a regularly scheduled scan set via the clients' local scheduler.
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So first check your agent config Start | standard LANDesk agent | Inventory Scanner and make sure that Run Inventory Scans | When IP address changes (mini scan only). This will help in the future. Also here is a godd description of the issue you are encountering: http://community.landesk.com/support/docs/DOC-4661 Also you should have a local scheduled task that is configured in the Agent config to run the Inventory scanner every X min/hours. This should also produce a inventory scan to the core.
So for 5,000 nodes I would try a managed script that does an inventory scan. There should already be a default one created. This should UDP, TCP, and Then DNS to perform lookups.
Well, maybe I already have enabled what I need and perhaps I haven't waited long enough. Below is a snapshot of the Inventory Scanner section from our Agent Configuration. As seen, I already have a check mark in the area of "When IP address changes" and there is a set schedule driven scan. Am I good? I just feel in the spring, following a push I would see many computers respond back with a message to the effect of a different agent responded back.
LANDesk version 126.96.36.199
So I would suggest that you lower the Schedule drive scan down a couple of days, maybe at least every 24 hours. If your machines are configured with a decent DHCP lease renewal time and they pickup a new IP (they should) you will get an updated inventory record. IMO the inventory scan is one of the most important parts of a healthy LDMS system and you should have the scanner run as frequently as your shop allows. Are the scans being rejected in the errorscan folder on your core?
Sorry for the delay in my response.
At first I lowered the scans to each hour and repushed the client to all workstations. The following day I altered the length of time to several days then pushed the update to all comptuers.