Smart Protection Network (SPN) uses cloud-based services and relies on DNS queries for lookups. To ensure fast response and minimum latency, the Deep Edge device must be configured with a DNS server. You can set up to three DNS servers.

The DNS servers must be able to support the volume of DNS requests made by Deep Edge. In general, before Deep Edge builds up its local DNS cache, two DNS requests will be made for each URL accessed. Make sure your DNS server is installed on a server with enough resources and performance to handle the extra DNS volume.

To reduce latency, each DNS server should have a fast network card and be installed on a fast network switch.

Trend Micro recommends on-site DNS servers versus ISP-provided DNS servers that are housed outside of the company's network. In general, ISP DNS servers have higher latency and do not support large numbers of DNS queries from a single IP address. Many ISP DNS servers have throttling mechanisms that limit the number of DNS requests per second and can affect Deep Edge's Web Reputation Services (WRS) performance.

To improve network response time and performance, try to place the DNS server as close to the Deep Edge unit(s) as possible to eliminate unnecessary network hops between the devices.

WRS and URL Filtering requests are made over HTTP port 80. Do not block the Deep Edge management IP address for these ports on the firewall.