Prerequisites

Table of Contents

• Virtual Appliance Requirements
• Networking Requirements
• DNSCrypt

Virtual Appliance Requirements

• You must be licensed for either DNS Security Essentials, DNS Security Advantage, Insights, or Platform. For more information, see Cisco Umbrella for Government Packages and Determine Your Current Package.
• Two virtual appliances (VAs) per Umbrella site—VAs must be deployed in pairs to ensure redundancy at the DNS level and to allow for updates without downtime.
• VA Specifications—At a minimum, each VA requires the following allocated resources:
  • Two virtual CPUs
  • Minimum 2 GB of RAM
  • 7GB of disk space.

Each VA can process millions of DNS requests per day using these specifications. If you believe your network will exceed this number, see Sizing Guide.

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Important

High-traffic site VAs should use two virtual CPUs and 2048MB of RAM per VA.
A high-traffic site is one that has more than 500 DNS queries per second coming from the overall network.

• Correct Date/Time—Ensure your hypervisor host has the correct date and time. The incorrect date or time can cause update or sync issues with the VAs. The VA syncs time independently and is always set to UTC by default.

VMware Requirements

• VMware ESXi (supported versions as per VMware)
  For more information, see VWware documentation.
• VMware Cloud on AWS

Microsoft Hyper-V Requirements

One of the following Windows Server operating systems:

• Windows Server 2012, SP1, or R2 (Standard or Data center), 2016 or 2019 with Hyper-V role
• Hyper-V Server 2012, 2012 R2, 2016 or 2019

Note: Deploying the virtual appliance through System Center Virtual Machine Manager (SCVMM) has not been qualified and is not officially supported.

Cloud Platform Requirements

• Microsoft Azure
• Amazon Web Services
• Google Cloud Platform

KVM Requirements

• KVM on Ubuntu Linux (supported LTS versions)
• KVM on Red Hat Linux (supported versions)

Nutanix Requirements

• Supported version of Nutanix AHV

Networking Requirements

Once VAs are deployed and ready to be utilized, endpoint clients must exclusively resolve DNS through the VAs and not your local DNS forwarders. This is usually accomplished through the network's DHCP configuration. For more information, see Local DNS Forwarding.

The following firewall/ACL requirements ensure VAs can communicate with the Umbrella cloud services and local DNS forwarders/servers. These requirements apply to each platform to which the VA is deployed.

SSH Support Tunnel

The tunnel must be established by the customer to the Cisco support team.
For more information, see On-Demand Tech Support SSH Tunnel for Virtual Appliances.

Networking: Additional Considerations

Intrusion Protection Systems (IPS) and Deep Packet Inspection (DPI)—If utilizing an IPS or DPI, ensure that traffic on port 53 TCP/UDP to and from the VAs is excluded from packet inspection, as Umbrella's DNS encryption methods might be flagged and dropped. If the VAs cannot successfully send and receive encrypted DNS packets, Umbrella displays a warning in the dashboard.

Network Address Translation (NAT)—If a routing device running a separate NAT is placed between endpoints and VAs, an endpoint's IP address will show as the NAT device's IP address in the DNS Umbrella dashboard. The endpoints must reach the VAs without being subjected to a separate NAT. If you are unable to remove a routing device with a separate NAT, you may have to run a separate set of VAs within that NAT. If you have any questions regarding this matter, contact Support.

HTTP Proxies / Content Filtering—Most solutions attempting to locally proxy, cache, or filter HTTP/HTTPS traffic between an endpoint and the internet require additional configuration to work in unison with VAs. Failure to adjust the configuration of these solutions before employing the VAs may result in the complete ineffectiveness of the VAs and Umbrella. For more information, see Using Umbrella with an HTTP Proxy. Solutions include:

• Transparent HTTP/HTTPS Proxy
• Standard/Caching HTTP/HTTPS Proxy
• Content Filtering via a hardware appliance

DNSCrypt

The VA supports DNSCrypt between itself and the Cisco public DNS resolvers (Umbrella). This means any information contained in the EDNS packets forwarded from the VA are encrypted by DNSCrypt and cannot be intercepted. For optimum protection, this feature is enabled by default.

Unencrypted traffic is considered a problem that should be resolved. When encryption cannot be established between your VA and the Cisco DNS service, your dashboard displays a warning. Encryption is established with a probe sent on port 53 (UDP/TCP) to 18.252.251.72 and 18.254.118.193 and if you have a firewall or IPS/IDS doing deep packet inspection and expecting to see only DNS traffic, the probe may fail. If the probe fails, it is retried on 443 (UDP/TCP) and then on 5353 (UDP). In other words, the encrypted packets may not match the expected traffic on that port. Review your firewall configuration if that is the case and open a case with Support if you believe that you are allowing this traffic.

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Introduction < Prerequisites > Deployment Guidelines