Loading

×Sorry to interrupt
This page has an error. You might just need to refresh it.
[NoErrorObjectAvailable] Uncaught ReferenceError: addCTracking is not defined
Failing descriptor: {markup://c:KM_ArticleThemeLayout}

Refresh

Cookie Preference Center

General Information on cookies

When you visit our website, we use cookies to ensure that we give you the best experience. This information does not usually directly identify you, but it can give you a more personalized web experience. Because we respect your right to privacy, you can choose not to allow some types of cookies by clicking on the different category headings to find out more and change your settings. However, blocking some types of cookies may impact your experience on the site and the services we are able to offer. Further information can be found in our

Cookie Policy.

Strictly Necessary

Strictly Necessary

Always Active

Strictly Necessary

Strictly necessary cookies are always enabled since they are essential for our website to function. They enable core functionality such as security, network management, and website accessibility. You can set your browser to block or alert you about these cookies, but this may affect how the website functions. For more information please visit www.aboutcookies.org or www.allaboutcookies.org.

Cookie Details‎

Performance

Performance

Performance

Performance cookies are used to analyze the user experience to improve our website by collecting and reporting information on how you use it. They allow us to know which pages are the most and least popular, see how visitors move around the site, optimize our website and make it easier to navigate.

Cookie Details‎

Please confirm your settings by refreshing the page.

Functional

Functional

Functional

Functional cookies help us keep track of your past browsing choices so we can improve usability and customize your experience. These cookies enable the website to remember your preferred settings, language preferences, location and other customizable elements such as font or text size. If you do not allow these cookies, then some or all of these services may not function properly.

Cookie Details‎

Advertising

Advertising

Advertising

Advertising cookies are used to send you relevant advertising and promotional information. They may be set through our site by third parties to build a profile of your interests and show you relevant advertisements on other sites. These cookies do not directly store personal information, but their function is based on uniquely identifying your browser and internet device.

Cookie Details‎

Advertising Cookies

Consent Leg.Interest

Select All Vendors

Select All Vendors

Select All Hosts

Select All

Clear Filters

Information storage and access

Apply

Confirm My Choices Reject All Allow All

My Subscriptions

Loading

Knowledge Base

After upgrading to NSX-v 6.4.0, you see the error: "Possible DHCP DOS attack seen on the host. Please refer to NSX Manager and VM Kernel logs for details." (53914)

Last Updated: 5/1/2018Categories: TroubleshootingTotal Views: 32347Language:
Chinese (Simplified)JapaneseEnglish

7 like this article

Subscribe to get an email
newsletter with new updates

7 people found this helpful Please provide article feedback:

Symptoms

after upgrading to NSX-v 6.4.0, you see these symptoms:

You see the error:

"Possible DHCP DOS attack seen on the host. Please refer to NSX Manager and VM Kernel logs for details."

In the /var/log/vsm.log file of the NSX Manager, you see entries similar to:

2018-04-09 08:29:27.877 CDT  INFO SimpleAsyncTaskExecutor-1 HostEventsResponseHandler:206 - - [nsxv@6876 comp="nsx-manager" subcomp="manager"] Host event occurred {eventname: DHCP_STARV, eventType: swsec, eventdescription: Possible DHCP Dos Attack!,eventdata null, eventTtl null, at host: host-141153, at dvPortId 1568, sourceMac 00:50:56:ae:1d:1c1568, occurence 11, at time null}

In the /var/log/vmkernel.log file of the affected ESXi host, you see entries similar to:

2018-02-27T04:39:04.957Z cpu21:1579031)WARNING: dvfilter-switch-security.throt: SwSecDhcpSnoopTx:600: nic-1579030-eth0-dvfilter-generic-vmware-swsec.1: Possible DHCP DosAttack on port 50331691(123) 1 times from Mac : 00:50:56:94:0f:69
2018-02-27T04:42:00.312Z cpu21:1579031)WARNING: dvfilter-switch-security.throt: SwSecDhcpSnoopTx:600: nic-1579030-eth0-dvfilter-generic-vmware-swsec.1: Possible DHCP DosAttack on port 50331691(123) 1 times from Mac : 00:50:56:94:0f:69
2018-02-27T04:42:03.314Z cpu13:687425)WARNING: nsx-dvfilter-switch-security: SwSecDhcpParse:255: nic-1579030-eth0-dvfilter-generic-vmware-swsec.1: No lease time option in DHCPACK
2018-02-27T04:42:03.314Z cpu13:687425)WARNING: nsx-dvfilter-switch-security: SwSecDhcpParse:255: nic-1579030-eth0-dvfilter-generic-vmware-swsec.1: No lease time option in DHCPACK

Note: The preceding log excerpts are only examples. Date, time, and environmental variables may vary depending on your environment.

Cause

This issue occurs because a new DHCP DoS related security feature was introduced in NSX-v 6.4.0, that may report false positives.

Impact / Risks

These are warning messages only, and have no operational impact on the your environment.

Collect a list of ESXi hosts and MAC addresses that are being reported, and confirm that they are valid Guest VM MACs or valid MACs allocated to an NSX Edge Services Gateway NIC.

Resolution

This is a known issue affecting VMware NSX for vSphere 6.4.x.

Currently, there is no resolution.

Workaround

To work around this issue, disable these warning messages. You can disable these warning messages either through an API call or through the NSX Manager Central Command Line Interface.

Notes:

This command only disables the DoS attack alerts. No other functionality will be disabled.

You will no longer see the alerts on the dashboard and vsm.log file, although the vmkernel.log file will still log the alerts.

Through the API call

To get the current status of the host notifications:

GET https://<NSXMGR_IP>/api/2.0/hostevents

To disable host notifications:

POST https://<NSXMGR_IP>/api/2.0/hostevents

Body:
<hostEventsDto>
<enabled>false</enabled>
</hostEventsDto>

Through the NSX Manager Central Command Line Interface

To get the current status:

CLI: get host event notification status

To enable/disable host notifications:

CLI: set host event notification enable/disable

Related Information

It is possible to track down a Guest VM DVPortID, from the CLI of an ESXi host that is being reported as impacted, using this command:

net-swsec --host-notifications -o getVMs

Example 1:

[root@vm:~] net-swsec --host-notifications -o getVMs
Affected DVPortIDs :
74

Track down the Guest VM connected to DVPortID 74, and determine if the DHCP DoS alert is valid.

Example 2:

[root@vm:~] net-swsec --host-notifications -o getVMs

Affected DVPortIDs :
No VMs under attack.

There are currently no Guest VMs on this ESXi host being reported as under a DHCP DoS attack.

Detectable by VMware SkylineTM

Actions

Copy

link to clipboard
copied!

Print

Language:
Chinese (Simplified)JapaneseEnglish

Attachments

Additional Resources

KB
•
End Of General Availability of the Free vSphere Hypervisor (ESXi 7.x and 8.x) (2107518)

KB
•
Download and Install VMware Fusion (2014097)

Results 1-2 of 2

Ask The Community

Get answers quickly from VMware experts in the community

Post Subject

CONTINUE IN COMMUNITIES

Related Products:

Related Versions:

Take Our Survey

Support Assistant