NTP Pool DNS servers

To direct our millions of NTP users to an appropriate server we run a customized DNS server. Many of the instances are offered by volunteers around the world. This page provides more information if you are interested in providing a (virtual) server to be used for DNS services.

Requirements for hosting a server

The NTP Pool DNS server usually runs on CentOS or Ubuntu LTS; either will work though Ubuntu LTS is preferred. We also have one instance running on FreeBSD (in a jail I believe) which is performing very very well, but our automation setup isn't as robust for configuring it.

If it's a virtual machine it needs to be something like KVM or BHyve based, not a "kernel container based" system (basically our setup process needs full root access to a kernel).

Operating System
I minimal-ish install of (64-bit, x86_64) CentOS or Ubuntu LTS. Our software also works with FreeBSD, but we prefer not maintaining the base system on other operating systems than Ubunutu and CentOS, so if the system runs FreeBSD we prefer getting a jail on a well maintained system.
Any two or more core 64-bit CPU from the last decade will do a nice job
Minimum 1.5GB, ideally 2-4GB to ease system maintenance tasks.
Disk space
8GB or more, again mostly to allow for system updates etc. There are no specific performance requirements for disk IO.
IP addresses
One routable IPv4 address, ideally also IPv6. If your network supports us announcing our anycast network then announcing our anycast prefixes is possible.
It used to be less, currently it's about 5-20Mbit/second per server (anywhere from 1-4TB data per month).

During certain times of the hour and the day the rate goes up significantly for a few seconds. If you are in a country with poor DNS server coverage but can't serve that many requests, we have tools to give you less traffic.
Regular DNS servers can't smartly respond with a "nearby" server out of several thousand and do so weighted, so we run a bit of quirky DNS software that can.
Our system configuration includes firewall rules, so no external firewall is needed. In case you operate one and need to apply rules, the necessary ports are:
  1. port 53 (UDP and TCP)
  2. port 443 (DNS over HTTP, UDP and TCP)
  3. port 22 (ssh)
  4. port 8052 and 8053 (mTLS authenticated monitoring)
  5. port 179 (for optional bgp setups)
Be sure to disable session tracking for port 53/udp if you do have a firewall.
We do the day-to-day management of the system.

If you are interested in helping with this, please email ask@develooper.com.