Apart from the virtualization of the machines another important thing in the virtual infrastructure is the networking. Proper DNS and routing is required for proper connectivity between hosts, Vcenter and other equipments.
There are two ways where you can configure DNS and Routing for the VSphere Hosts. One option is from the DCUI and other option is using the Vsphere Client.
Method 1.) Login to the DCUI shell and navigate yourself to the Configure Management Network -> DNS Configuration
The screen will look like this.
You can specify the primary DNS name server and secondary DNS server which will be used to resolve names for the internal clients and as well as external routable names as well.
In the last option you can specify the host name that will be used in the vsphere server for connection.
Method 2.) Using Vsphere Client
navigate yourself to the
ESXi host -> Configuration -> DNS and Routing
you can see all the values assigned (if they have been assigned previously) if you want to change or add the values click on properties
After Clicking on properties you will get a window like this
Option 1.) Specify the name of the host. In my case it is esx2. ( Very Obvious Name)
Option 2.) Specify the domain name to which the host is connected. In my case it is routemybrain.com which is again obvious.
Option 3.) Obtain DNS server automatically. If you have a default gateway set in your routing environment then this option will be useful. You just have to specify the network Interface to which that network is connected and it will automatically resolve the queries with the help of the default router. To be frank I have never tested this setting.
Option 4.) You can specify the DNS here. Specifying only one dns server will also work here.
Option 5.) Most probably all your hosts would be part of the same domain but for e.g. if instead of specifying the FQDN of the host I specify only the name like esx2 then this domain is appended at the end of each query to find the host.
The Routing tab of the same window has only one setting. It is the default gateway. All the requests if not fullfilled is sent out the default gateway.
You can verify the DNS entries from the esxi shell as well. The DNS entries are store in /etc/resolv.conf