- You must be licensed for either DNS Security Essentials, DNS Security Advantage, Insights, or Platform. For more information, see Umbrella Package Comparison.
- 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:
- One virtual CPU
- Minimum 512MB of RAM (1GB RAM recommended)
- 7GB of disk space.
Each VA is able to process millions of DNS requests per day using these specifications. If you believe your network will exceed this number, see Appendix B – Sizing Guide.
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.
- VMware ESX or ESXi (supported versions as per VMware)
- VMware Cloud on AWS
One of the following Windows Server operating systems:
- Windows 2008 R2 Server with Hyper-V role
- Hyper-V Server 2008
- Windows Server 2012, SP1, or R2 (Standard or Datacenter) or 2016 with Hyper-V role
- Hyper-V Server 2012 or 2012 R2 or 2016
Note: Deploying the virtual appliance through System Center Virtual Machine Manager (SCVMM) has not been qualified and is not officially supported.
- Microsoft Azure
- Amazon Web Services
- Google Cloud Platform
- KVM on Ubuntu Linux (supported LTS versions)
- KVM on Red Hat Linux (supported versions)
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 both VMWare and Hyper-V deployments.
53 TCP + UDP
Your DNS Forwarder IPs
Standard and Encrypted DNS—If utilizing a default deny firewall ruleset for local traffic, add the internal IP addresses of any local DNS forwarders/servers to the firewall ruleset, so that the VAs forward local queries accordingly. Note that these ports are used to establish DNSCrypt. For more information, see DNScrypt.
443 TCP + UDP
HTTPS—Used for registration, health checks, and updates from Umbrella.
ocsp.digicert.com and crl4.digicert.com use a CDN and are not assigned static IP addresses, thus are subject to change. Currently, these domains resolve to the following IPs:
In addition, 443 is used as failover for DNSCrypt if 53 is unavailable and talks to 22.214.171.124 to probe. For more information, see DNSCrypt.
HTTP—Used for fetching the SSL revocation list to initiate the HTTPS connection.
NTP—Protocol to synchronize time.
Updates to the VA.
22 25 53 80 443 or 4766 TCP
Required for the customer-initiated SSH support tunnel. For more information, see On-Demand Tech Support SSH Tunnel for Virtual Appliances.
5353 TCP + UDP
5353 is used as failover for DNSCrypt if 53 or 443 is unavailable. For more information, see DNSCrypt.
53 UDP + TCP
Required for DNS to flow between client and VA. TCP optional.
Required for Chromebook client trusted network feature.
Used to send user/IP mapping (one-way) from the Active Directory (AD) connector to the VA.
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.
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 DNS Safeguard's DNS encryption methods might be flagged and dropped. If the VAs cannot successfully send and receive encrypted DNS packets, DNS Safeguard 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 Safeguard 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 in order 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 DNS Safeguard. 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
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 126.96.36.199 and 188.8.131.52 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.
DNSSEC is a set of security extensions for DNS that provides the means for authenticating DNS records. Currently, the Cisco Umbrella VA does not support DNSSEC for resolving DNS queries for internal or external domains.