Event ID - 15111

Event Id15111
SourceMicrosoft ISA Server Job Scheduler
DescriptionISA Server denied the assignment of the IP address to the network adapter since the IP address offered is not included in the network IP addresses. This could indicate a possible DHCP attack. The Record Data contains the suspicious DHCP packet.
Event InformationAccording to Microsoft :
CAUSE :
This event occurs when the DHCP anti-poisoning intrusion detection mechanism detects a malicious or invalid offer.

SOLUTION :
Follow the instructions provided in the description for the related alert. To do this, in the console tree of ISA Server Management , click Monitoring, then click the Alerts tab. In the list of alerts, select the relevant alert. The alert description displays in the alert details pane.
Reference LinksEvent ID: 15111 Of Source ID:Microsoft ISA Server Job Scheduler

Catch threats immediately

We work side-by-side with you to rapidly detect cyberthreats
and thwart attacks before they cause damage.

See what we caught

Did this information help you to resolve the problem?

Yes: My problem was resolved.
No: The information was not helpful / Partially helpful.