6.5.1

2 Verify that DNS reverse lookup returns a fully qualified domain name when queried with the IP
address of the vCenter Server.
When you upgrade vCenter Server, the installation of the web server component that supports the
vSphere Web Client fails if the installer cannot look up the fully qualified domain name of the
vCenter Server from its IP address.
Reverse lookup is implemented by using PTR records.
3 If you use DHCP instead of a manually assigned (static) IP address for vCenter Server, make sure
that the vCenter Server computer name is updated in the domain name service (DNS). Test the
update by pinging the computer name.
For example, if the computer name is host-1.company.com, run the following command at the
Windows command prompt:
ping host-1.company.com
If you can ping the computer name, the name is updated in DNS.
4 Ensure that the ESXi host management interface has a valid DNS resolution from the vCenter Server
and all instances of vSphere Web Client. Ensure that the vCenter Server has a valid DNS resolution
from all ESXi hosts and all instances of vSphere Web Client.
5 If you intend to use Active Directory as an identity source, verify that it is set up correctly. The DNS of
the vCenter Single Sign-On Server host machine must contain both lookup and reverse lookup
entries for the domain controller of the Active Directory.
For example, pinging mycompany.com should return the domain controller IP address for
mycompany. Similarly, the ping -a command for that IP address should return the domain controller
host name.
Avoid trying to correct name resolution issues by editing the hosts file. Instead, make sure that the
DNS server is correctly set up.
6 Before the upgrade, select the domain user to use for upgrading vCenter Server. Give that domain
user exclusive administrator permission for vCenter Server, not as part of a Windows Administrators
group.
Your network is ready for vCenter Server upgrade.
What to do next
Prepare other components of your environment.
vSphere Upgrade
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