Answer

PROBLEM

When a machine is scanned for the first time, the operating system is not determined if it cannot connect via SMB or SNMP. The next time the same machine is scanned the operating system is determined correctly.

ENVIRONMENT

• GFI LanGuard
• All supported environments

CAUSE

This issue is usually caused by network instability. It could be that network traffic is slow, or there were lots of collisions on the network and the packet did not get resent.

SOLUTION

Follow these steps to increase the number of retries:

1. Open GFI LanGuard console.
2. Click on the Configuration Tab.
3. Expand Scanning Profiles and select the type of scanning profile you wish to modify.
4. From the right pane, select the scanning profile by clicking Edit this profile….
5. Click Scanner Options and expand Network Discovery Options.
6. Under the Number of retries (default 1) increase the number of attempts.

NOTES:

• GFI LanGuard supports SNMPv1 and SNMPv2c.
• SNMPv3 and SNMP over TLS/DTLS are not supported.