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vlan and vswitch

This is morein to design question than troubleshooting. Hope someone give some idea.
We have Esxi environments with class c ip scheme.
We are now running out of IP for servers.
Either we have to come up with another class c IP scheme and create multiple port group in single vswitch or change the ip address to class B.

What is the best option you would recomend to accommodate more servers?
2 Solutions
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Running out of IP Addresses for VMware ESXi servers, or virtual machines?

Create a class B.
Bryant SchaperCommented:
Before you do that you may also want to consider what is on the C and if you are better server with multiple C subnets to create barriers, this will require intervlan routing however so that network 192.168.0.x can talk to machines on 192.168.1.x
If it is just one or a few subnets you need to adjust you can supernet the class C addresses to combine multiple class C ranges into a single logical subnet.  You would need adjacent class C subnets not in use to make it work and you would likely need to know a bit about subnetting your addresses.

For example, if you were using and you needed twice as many addresses you could do which would consume the adjacent subnet and make one range of  You would need to possibly adjust some routing on your network but it should be fairly simple, as long as you have that adjacent IP range, and it falls within the same range when you adjust the mask (for example, my previous example of a /23 mask wouldn't work for and to combine them).  If you don't understand that concept you might need to read up on subnetting.
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sara2000Author Commented:
i am running out of vms ip address . Right now my vms ip are 192.168.1.*/24 and my iscsi storage ips are 192.168.2.*.

suppernetting 192.168.1.*/23 is not going to help since the adjacent 192.168.2.*/24 is being used by iscsi.
my network admin suggested me to create another port group in the existing vswitch (192.168.1.*/24) .
and name this as lan2 and give ip address for the server in the network 192.168.3.*/24).
Creating a port group is not an issue for me, but what else i have to do to make sure that servers will talk, is that right approach?
i am willing to change the ip from class c to class b, this can be lot of problem . down time and changing nat ip etc.
You mentioned about inter vlan , is it something in the vmware or the network guy will do that?
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
You mentioned about inter vlan , is it something in the vmware or the network guy will do that?

both, you need to configure the physical switches, and also the virtual switches, to use VLAN Tags.
You can combine and into one logical subnet with a mask of assuming you aren't already using for something else.

Your port groups will just reference a VLAN ID and that just needs to match the VLAN ID on our switches.  You shouldn't need to change any of that.  You just need to adjust the addressing on that subnet.  All the hosts would need to be updated with the new subnet mask and the router interface on that subnet would need to get the new mask as well.  If you have a DHCP scope for that subnet you will also need to recreate it since I don't think you can adjust the mask on an existing scope.  

The only other option would be to leave what you have alone, then create a new port group and VLAN ID on your network switches and use the address range and do the intervlan routing just like you do now with the subnets you have.
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