I'd like to add some more IPs to my single ESXi server that I have through a hosting provider. When the server was set it up, I was given a /29 and was left with five IPs to use. But, there's something baffling me on how I would add more IPs.

My server only has one NIC, and from what I understand, one NIC can only be assigned one gateway at a time (the new IPs would have a different gateway). I asked my data center on how this would work, and they simply responded that the new IPs would be on the same private VLAN that I am on right now and I could set it up in the OS config. But, how does having the new IPs in the same VLAN make a difference? I set up pfSense (which is a virtual machine and all the VMs route through it using NAT 1:1) to have the gateway on my first range of IPs. So wouldn't pfSesne need a whole new interface/WAN to even add these IPs?

I'm obviously missing something but I have no idea what it is...

pfSense config for the static WAN interface (the IP is a public IP, so I blanked it out):

pfSense config

It'll probably help to mention that then to assign signle IPs off to my VMs, all I do is add in the IP as an alias, and it works. But I see that it allows me to add an IP in a completely different subnet, so maybe all I need to do is just add in the new IPs here and not even touch anything else as it's all on the same VLAN?

pfSense virtual IPs

  • You don't -need- more than one default gateway. Does this help? I'm trying to understand the rest. – gparent Apr 28 '13 at 4:16
  • Sorry, I'm no networking expect... if the gateway of the new IP range was not added, wouldn't it not assign the new IPs correctly as they're in a completely different subnet? I also just realized pfSense does allow to add another gateway easily, but of course, it won't let me due to only one interface... drop.taylorjasko.com/XcQz/4n2EEqKs – Taylor Jasko Apr 28 '13 at 4:27
  • A default gateway is where you go when trying to reach a network you have no route to. It doesn't make sense to have more than one unless you want redundancy when you can't reach one (which seems to be why pfSense is letting you pick existing ones or to add a new one) – gparent Apr 28 '13 at 4:35
  • Ah ha, so gateways are not even used when assigning the IPs (I thought they were required). I just updated the question... I believe all I need to do then is just add the new IPS as an alias/virtual IP and then just use NAT1:1 to assign them out. I feel a bit dumb if that's all that needs to be done... hehe – Taylor Jasko Apr 28 '13 at 4:37

You do not need more than one default gateway since a default gateway by definition is where you go when you do not have a route for your destination. All your IPs being on the same VLAN means you do not need to tag VLANs on your interface (or if you do, it's all the same one).

Assign the new IPs to your interface and you should be good to go.

  • Ah ha, makes sense. Was overcomplicating this too much. Didn't think it was just that easy just to assign the IPs to the interface without setting anything else up. Thanks gparent! :) – Taylor Jasko Apr 28 '13 at 4:44
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    I think we all eventually encounter a situation that doesn't make sense in our heads until we just do it. Don't worry :) – gparent Apr 28 '13 at 4:45

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