Timestamps in scanning, scanning targets , last scan column

[TK_AT_HBK]

i am having about 50 ip-range-scan targets with a size of /16 or /21 or similar.

i managed to schedule them so that only a few are starting at the same time.

we only run 1 single server..

looking at the aforementioned overview in the local admin console the last scan column seems to be a timestamp that i can not relate to anything consistently.

smaller ranges seem to have a timestamp of " when the scan finishes".

other seem to have a timestamp that seems to be when being added to the queue.

looking than also at the menu item of scanning , scanning status, scanning queue i am not able to identify ips that should be worked on .

sometimes the queue field has a number of a few thousands, sometimes a few hunderds but nothing that would compare to a / 16 scan.... and scans that should be in the queue ( 4 scans with mask of /16  starting at 12 noon).

also the menu scanned in the last 24 hrs / 7 days menu will not really represent what was scheduled or indicated in last scan column or in the queue menu ...

is there a KB that explains the generic approach of how the ip range scanning works , queues are populated and results are being shown .

for me it is not the parallel or sequential single IP check , but rather the 1 plus N scan schedules .

can you also explain what happens if the queue shows more than a number of 256000 ... ?

if and how schedules get skipped, if whatever queue/buffer is "full".... i have seen a few ip range schedules that apparently did not run ( lastscan column date ... ) for no obvious reason.

thanks for clarification.

[Obi_1_Cinobi]

Hello there!

256000 scans for a single scan server is quite a lot, and this would explain why some of your assets aren't being scanned at all. As a rule of thumb, we recommend one scan server per 1,000-5,000 assets as described here: https://community.lansweeper.com/t5/installation/which-lansweeper-setup-is-right-for-you/ta-p/64593

To clarify, Lansweeper does not support CIDR notation for setting up IP range scanning targets. IP range scanning targets can only be defined by setting a start and end IP address for the range you want to see scanned. The size of the IP range you have entered will define the scan time. When manually entering the IP range in Lansweeper, you will be presented with an estimated scan duration to assist you with determining the size of your scanning ranges.

Lansweeper does not have any limitations on the size of the subnet that is being scanned. But depending on how frequently you wish to scan your assets, the scan time will need to be taken into account though. For example, if you wish to scan your assets each hour, you must ensure that your scanning targets can complete scanning within that hour. We recommend spreading the load on your scanning server by ensuring that not all scanning targets start simultaneously. A staggered approach is preferred to make the most of the available scanning threads.

Keep in mind that you can expand your available scanning threads by spreading your scanning targets across multiple scanning servers. You can set up a combined maximum of 99 scanning threads per scanning server under Configuration\Server Options, divided between Computer threads and IP threads (one extra thread is allocated to your scan service):

• IP Threads determine how many IPs can be treated during scanning.
• Computer Threads determine how many Windows computers can be scanned simultaneously.

We can't provide detailed instructions on how much you will need to spread the scanning of your subnets as this will depend on the type of assets you are scanning, your scan intervals for your Windows scan items, the CPU available for your scanning server, network speed... to name a few.

Some recommendations though:

• Increase the number of computer threads and IP threads your Lansweeper server can use under Configuration\Server Options, scroll down to Service Options. You could experiment with this setting. It's a CPU-dependent setting. We recommend monitoring your Lansweeper server's CPU usage to find the sweet spot here.
• Lower the frequency at which you're scanning specific scanning targets by modifying your schedules under Scanning\Scanning Targets and make sure they kick off at different times.
• Lower the frequency at which certain items are scanned for Windows computers under Scanning\Scanned Item Interval. More on this functionality can be read here: https://www.lansweeper.com/knowledgebase/managing-how-often-specific-data-is-scanned/