Subnet question

Sid_F used Ask the Experts™
I have four nics in a server, each of the networks connected to each nic require access to the internet.
The nics ips are below, the default gateway is so the first nic works perfect. What subnet should I use for all the networks so they can all communicate with the gateway, thanks.

10.10.224 /24
10.10.225 /24
10.10.226 /24
10.10.227 /24
Watch Question

Do more with

Expert Office
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
Not sure exactly what you are trying to accomplish but the subnet mask to use to have all the nice in the same network would be use a /22  subnet
Qlemo"Batchelor", Developer and EE Topic Advisor
Top Expert 2015

If you want the networks to be isolated from each other, you would have to run RRAS on that server, and use it as default gateway (with the correpsonding NIC address for each network). The default gatewy always needs to be on the same subnet, so you cannot use the correct one directly but on the first subnet.
On the server your only gateway setting should be on the first NIC.


Qlemo"Batchelor", Developer and EE Topic Advisor
Top Expert 2015

If you do that (expand the network mask), what sense does using 4 NICs with separate sub-subnets make?
Brian MurphySenior Information Technology Consultant

Depends on whether or not you are using the same switching architecture.

You can have 4 NICs in one server just assign a default gateway to one of them and use static routes.

This is highly contingent on DNS.  You could install Windows DNS on that server and create a "Forwarder" if each NIC represents a different DNS domain then assign the suffix domain on the advanced properties of the NIC configuration.  Simply create a stub zone or forwarder for each of the four.

Does each NIC range of IP's get DHCP addresses?  Where is the DNS for Internet resolution come from?

Are you trying to use that server with 4 NICs as a hub?  Like internet sharing?

Again, assign a gateway to the NIC that has the actual Internet connection.  Install Microsoft DHCP and DNS on that server.  You can bind scopes for those ranges by static IP assigned to your NICs.

You have or want 4 networks of 24-bit mask.

I would consider that you are using an internal IP range.  If this were a true private network I would advise you leverage the correct IPV4 address ranges as defined by RFC-1918.

Technically your 10(dot) range is a class A. IP addresses: --

This is strategically important as it relates to routing.  You can assign 24 bit masks to 4 networks but your switch is layer 2.  Something has to route that traffic between those networks.   This impacts your DHCP scope configuration.  The impacts are too many for listing.

If you have a single internet connection that connection terminates to a single device or modem.  Depending on that equipment that "modem" might terminate to a Internet port on a layer 2 switch or hub that offers DHCP ability from that device.  

The point being the Internet connection uses a single routable IP that might be a NAT or might be a PAT (Cisco PIX Firewall).

You are basically NAT'ing all your internal IP with a address based on information provided.

I would start with one connection, one Gateway and verify your connection.  Discover your ISP routable IP with

Take a look at this basic diagram.  Would you agree your in the box?  If you have other servers, other switches and so forth you need the routing piece.


Do more with

Expert Office
Submit tech questions to Ask the Experts™ at any time to receive solutions, advice, and new ideas from leading industry professionals.

Start 7-Day Free Trial