This document will cover the two options in setting up a Demilitarized Zone -DMZ host and DMZ subnet on RV160X/RV260X series routers.
A DMZ is a location on a network that is open to the internet while securing your local area network (LAN) behind a firewall. Separating the main network from either a single host or an entire sub-network, or "subnet" ensures that people visiting your website server via the DMZ, won't have access to your LAN. Cisco offers two methods of using DMZs in your network that both carry important distinctions in how they operate. Below are visual references highlight the difference between the two operating modes.
||Single host, fully open to the internet
|Subnet / Range
||Multiple devices and types, fully open to the internet. Available only on RV260 hardware.
Regarding IP Addressing
This article makes use of IP addressing schemes that carry some nuance in their usage. In planning your DMZ you may consider using either a private or public IP address. A private IP address will be unique to you, only on your LAN. A public IP address will be unique to your organization and is assigned by your Internet Service Provider. To procure a public IP address you will need to contact your (ISP).
Configuring DMZ Host
The information required for this method includes the intended host's IP address. The IP address can be either public or private, but the public IP address should be in a different subnet than the WAN IP address. The DMZ Host option is available on both the RV160X and RV260X. Configure the DMZ Host following the steps below.
Step 1. After logging into your routing device, in the left-hand menu bar click Firewall > DMZ Host.
Step 2. Click the Enable checkbox.
Step 3. Enter the designated IP address of the host you wish to open up to WAN access.
Step 4. When satisfied with your addressing, click the apply button.
Note: If you're working with an RV160X series only and want to skip to the verification instructions,click here to move to that section of this document.
Configuring Hardware DMZ
Available to the RV260X series only, this method requires different IP addressing information based on the method you choose. Both methods indeed use subnetworks to define the zone, the difference being how much of the subnetwork is used to create the demilitarized zone. In this case, the options are - all or some. The Subnet (all) method requires the IP address of the DMZ itself, along with the subnet mask. This method occupies all of the IP addresses belonging to that subnetwork. Whereas the Range (some) method allows you to define a continuous range of IP addresses to be located within the DMZ.
Note: In either case you will need to work with your ISP to define the subnetwork's IP addressing scheme.
Step 1. After logging into your RV260X device, click WAN > Hardware DMZ
Note: The screenshots are taken from the RV260X user interface. Below is the screenshot of Hardware DMZ options that will be displayed on this page.
Step 2. Click the Enable (Change LAN8 to DMZ port) checkbox. This will convert the 8th port on the router into a DMZ only "window" to services that require enhanced security.
Step 3. After clicking Enable an informational message displays below the selectable options. Review the details for points that may affect your network and click the OK, I agree with the above checkbox.
Step 4. The next step splits into two potential options, Subnet and Range. In our example below we've selected the Subnet method.
Note: If you intend to use the Range method, then you will need to click the Range radial button, then enter the range of IP addresses assigned by your ISP.
Step 6. Click Apply (in the upper right hand corner) to accept the DMZ settings.
Confirming the DMZ is setup properly
Verifying the DMZ is configured to appropriately accept traffic from sources outside of its zone, a ping test will suffice. First though, we'll stop by the administration interface to check the status of the DMZ.
Step 1. To verify your DMZ is configured, navigate to Status & Statistics, the page will load the System Summary page automatically. Port 8 or "Lan 8" will list the status of the DMZ as "Connected".
We can use the trusty ICMP ping feature to test if the DMZ is operating as expected. The ICMP message or just "ping", attempts to knock on the door of the DMZ. If the DMZ responds by saying "Hello" the ping is completed.
Step 2. To navigate your browser to the ping feature, click Administration > Diagnostic.
Step 3. Enter the IP address of the DMZ and click the Ping button.
If the ping is successful you will see a message like the above. If the ping fails, it means the DMZ is unable to be reached. Check your DMZ settings to ensure they are configured appropriately.
Now that you've completed the setup of the DMZ, you should be able to begin accessing the services from outside the LAN.