Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have some servers at a colocation. They've given us an IP range, subnet and gateway. Now we have run out of IP addresses and they've given us a new range of IPs but with a different subnet and gateway.

We have a Juniper NetScreen firewall and a load balancer, and I am not sure how to proceed in order to be able to use these new IPS that are on a different subnet.

Do I need to setup a new VLAN? on our firewall?

I tried adding one of the new IPs on one of our servers, with the new subnet and gateway. I could ping the alternate gateway, but could not ping the assigned IP from outside or from inside.

share|improve this question
Are you able to ping the gateway of the new subnet? – RWC Oct 30 '12 at 18:08
Please give us more information about the current setup. Then we can help you better. A diagram would help. – Raffael Luthiger Oct 30 '12 at 20:36

You'll need to add the new subnet to your WAN Interface on your Webscreen device. You should access this through the WebGUI.

Once inside the WebGUI, select your WAN Interface and select 'edit.' I'm not familiar with the exact interface myself, but you should have the ability to add another host range and you'll want to mark it as 'secondary.' From there you'll be able to assign the IPs in the load balancer out to your devices. Your balanced servers will likely have their addresses NAT'd on the LB, so ensure that you map them correctly.

share|improve this answer

You'll have to ask the network admins at your colo to configure a route between those two subnets or give you one larger subnet and consolidate all your servers into that, but that would require a lot of manual reconfiguration to your servers.

share|improve this answer
This is not true. The new subnet will be added as a secondary to the Vlan for the customer at hand, in this case, BGuy2010. He likely has a port tagged with a vlan with these subnets on the Colo's equipment and chances are, if we had the gateways for both subnets, we'd be able to ping them. – RWC Oct 30 '12 at 18:06
This assumes that both subnets belong to the same switch fabric. My point is that it's probably out of his hands, as it's not his equipment, and will need to be escalated to the colo's network group. – Rob C. Oct 30 '12 at 18:15

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.