hanges I need to do in vCenter and ESXi when changing subnet mask

j_rameses used Ask the Experts™
I am in the process of changing the subnet mask in our network from to
I already changed all our printers, appliances such as Barracuda device, fax server, firewall, etc.
I just configured a new class 3 managed switch with the new subnet of 255.255.252.  The ip for it I used one in the range. I rather keep all my appliances on that same subnet mask value.
Now I am in the part where I have our esxi Hosts and vCenter and all our other VMs in our network that are statically assigned with previous subnet of
We also run VMware view environment for half our users(eventually all users will have a vDesktop).
When is the process of changing the subnet mask in our environment without knocking our our network.

Also, our management in each host machine is on the same subnet as all our devices.
I was informed it is best practice to have our management port on a separate subnet.
What is the process of doing this?
I am clueless in that process.
Also, is it possible to share vMotion on that same subnet? Since vMotion doesn't get used that often.
Right now both management and vMotion share two nics ports.

Pls advice.
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Top Expert 2008
Did you use FQDN for the hosts when you registered them in vCenter (not ip addresses)?

For the ESXi hosts it should be a question of changing the management ip (and VLAN) for each of your hosts and changing the DNS record.

No matter if you're using vCSA or Windows it should be fairly straight forward to change the ip of the vCenter host. Just make sure you update your DNS records.

I recently did this for a customer, but you are also have a View environment running, and I'm not sure if it will remain 100% unaffected while doing this.

Also, if you have used ip addresses instead of FQDN, the process will be a bit different as you will need to remove hosts from vCenter and add them again (+loosing historical stats).

Preferably you should have vMotion on a seperate non-routable network (unless you plan to do long distance vmotion).

Good luck!


what is the old subnet and the new subnet please? (network name & metric or IP & mask please)

with a bit of planning a subnet increase can be done without downtime or disruption, but sometimes you simply cannot avoid it.
j_ramesesInfo Sys Mngr
Steve, I scrapped the idea of changing the subnet mask to get more IPs.
Instead I created four separate vLANs:

That was that I choose.

I did put vMotion on a separate vLAN as suggested.
I decided not to monkey around with the servers and appliances.
I left them as is.
Fair enough. glad you've sorted it.
j_ramesesInfo Sys Mngr


Wasn't sure how to distribut points. So I gave lastr the bulk for suggesting vMotion separate.

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