6.0.3

Table Of Contents
Authenticating User Credentials in Case of Connectivity Problems
If the Active Directory (AD) domain server is not reachable, you can log in to the ESXi DCUI by using user
name and password authentication to perform emergency actions on the host.
In exceptional circumstances, the AD domain server is not reachable to authenticate the user credentials on
the smart card because of connectivity problems, network outage, or disasters. If the connection to the AD
server is lost, you can log in to the ESXi DCUI by using the credentials of a local ESXi user. This lets you
preform diagnostics or other emergency actions. The fallback to user name and password login is logged.
When the connectivity to AD is restored, smart card authentication is enabled again.
N Loss of network connectivity to vCenter Server does not aect smart card authentication if the Active
Directory (AD) domain server is available.
Using Smart Card Authentication in Lockdown Mode
When enabled, lockdown mode on the ESXi host increases the security of the host and limits access to the
DCUI. Lockdown mode might disable the smart card authentication feature.
In normal lockdown mode, only users on the Exception Users list with administrator privileges can access
the DCUI. Exception users are host local users or Active Directory users with permissions dened locally for
the ESXi host. If you want to use smart card authentication in normal lockdown mode, you must add users
to the Exception Users list from the vSphere Web Client. These users do not lose their permissions when the
host enters normal lockdown mode and can log in to the DCUI. For more information, see “Specify
Lockdown Mode Exception Users,” on page 186.
In strict lockdown mode, the DCUI service is stopped. As a result, you cannot access the host by using smart
card authentication.
ESXi Security Best Practices
Follow ESXi security best practices to ensure the integrity of your vSphere deployment. For additional
information, see the Hardening Guide.
Verify installation media
Always check the SHA1 hash after downloading an ISO, oine bundle, or
patch to ensure integrity and authenticity of the downloaded les. If you
obtain physical media from VMware and the security seal is broken, return
the software to VMware for a replacement.
After downloading media, use the MD5 sum value to verify the integrity of
the download. Compare the MD5 sum output with the value posted on the
VMware Web site. Each operating system has a dierent method and tool for
checking MD5 sum values. For Linux, use the "md5sum" command. For
Microsoft Windows, you can download an add-on product
Check CRLs manually
By default, an ESXi host does not support CRL checking. You must search for
and remove revoked certicates manually. These certicates are typically
custom generated certicates from a corporate CA or a third-party CA. Many
corporations use scripts to nd and replace revoked SSL certicates on ESXi
hosts.
Monitor the ESX
Admins Active Directory
group
The Active Directory group used by vSphere is dened by the
plugins.hostsvc.esxAdminsGroup advanced system seing. By default this
option is set to ESX Admins. All members of the ESX Admins group are
granted full administrative access to all ESXi hosts in the domain. Monitor
Active Directory for the creation of this group and limit membership to
highly trusted users and groups.
vSphere Security
198 VMware, Inc.