A lot of this depends on how you have your machines configured.
There is a setting in the agent configuration section where you set up the frequency of the inventory scanner to have it run a scan on IP address change. This will make machines update as it happens.
Afterwards, you should still be able to reach the machine via hostname. You can check on the core server under Configure-Agent Discovery Options and see if IP is checked. If it is, try unchecking it and just using DNS. This should allow you to contact machines ok, but the inventory record will still have the old IP until that machine scans back in.
Additionally, once the client machine scans its next inventory scan, it will update the new IP to the core... so technically if you just wait long enough, the info should update accordingly.
...how the core server can scan the inventory or to contact these clients again?
It is not the Core that finds the client for an inventory scan. The client runs the scan by default every day and contacts the Core Server. It also by default runs a scan on IP Address change and sends that to the Core Server.
If the IP Address has changed and the client did not or was unable to send an updated scan to the Core, then the Core cannot contact a client by default. However, there is a discovery option that you can set to change from using the Inventory IP address to the DNS address. Of course if both DNS and inventory are wrong, you are out of luck.
I have reconfigured the agent configuration and updated to agent already.But an inventory data of this client doesnot change (I setup the lacal scheduler to scan inventory everyday at 9.30 AM).
Why the inventory data of this client doesnot change?
If the inventory information doesn't update, it means an Inventory Scan has not been processed. This can have several reasons. I'll try to work them down in a logical line.
Inventory Service on the Core isn't running. If the service isn't running, clients can't talk to it and do not send inventory.
Inventory Service rejected the scan-file because a field in the scan-file was bigger than the database allowed. If this is the case, you'll see an error in the Core's NT Application Event-log. The errors will be from the "LANDesk Inventory Service" and in the 4xxx range. If this is the case, I'd suggest you open a case with LANDesk support, and work with them through there, as it'll be faster to fix it over the phone than through here.
Client could not contact Core. In addition to the Inventory Service being down, there's wonderful stuff like DNS messing you up. I.e. - if the Core has got an IP of 126.96.36.199 but the Client is resolving the Core's name to 456.456.456.456 (I know the IP doesn't exist, it's just to make the point) you won't be getting anywhere. Go to the client and ping the Core - see what you get.
That SHOULD cover most problems. The easiest thing will be to make sure that Your Core has the inventory Service running and other clients can reach it.
If that's the case, number 2 + 3 should be the most likely reasons :).
LANDesk EMEA Technical Lead.
I found that the error in the Core's NT Application Event-log is in the 4xxxx range so i'll open this case with LANDesk Support.
Thank you to everyone.