In the event the root password is unknown,  connect to the ESX host console and restart the machine.

1. When the ESX host boots to the grub menu, hit the “a” key.
2. Add the command  “single” to the string and click enter
3. Wait for ESX to go through the boot process
4. At the command prompt type “passwd.”
5. Enter your new password.
6. Restart the host ie.  shutdown -r now

This process is only used to reset a lost or forgotten password. 
A video demo of this process is shown on my virtualisation website http://www.elasticsky.co.uk/videos

In a infrastructure with multiple networks,  it can be necessary to configure the routing on the ESX hosts rather than at the router.

This is  achieved using the below command

route add – net <network ID > netmask <subnet mask> gw <gateway interface>

ie :   route add -net 10.44.0.0 netmask 255.255.0.0 gw 192.168.0.12

In the above example,  all traffic for the 10.14.X.X network will be routed via 192.168.0.12

Note:  This route will not be persistent through reboots.  If the ESX host is restarted the route will need to be re-added. 

To ensure the route is persistent add the command to the bottom of the following config  file using a text editor /etc/rc.local

For example

Change directory  –  cd /etc/
Open Text Editor – nano rc.local
Specfiy the route at the end of the file  - route add -net 10.44.0.0 netmask 255.255.0.0 gw 192.168.0.12 
Exit Text Editor  - ctrl -x , Yes to confirm