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.
The production servers run on setups as described below, though we've also started testing an "appliance" that can run in a virtual machine or from a USB stick or compact flash with minimal setup. If you are able and interested in helping us test this, please see the pgeodns wiki.
Requirements for hosting a server
The NTP Pool DNS server usually runs on CentOS or Ubuntu LTS; either will work though CentOS is preferred. We also have one instance running on FreeBSD (in a jail I believe) which is performing very very well.
If it's a virtual machine, it needs to be a Xen or KVM based one if the server is going to be part of the anycast setup. The "container" systems (OpenVZ) don't have the required network interfaces to work. VMware will probably work, too.
- Operating System
- Basically just a 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 just getting a jail on a well maintained system. We can also run on Mac OS X 10.6+, but again someone else should apply system updates etc in that case.
- Faster is better. About 2 CPU cores, in the ballpark of 2GHz or faster is best. Almost any CPU from the last 4-5 years will do a nice job, though it has to be a 64-bit system.
- 1GB is comfortable, less is okay but not less than 512MB.
- Disk space
- 4-5GB is plenty. It can be just about as slow as you can imagine and it'll be fine.
- IP addresses
- One routable IPv4 address. IPv6 is also nice, but not required. If your network supports us announcing our anycast network then we like doing that, see below for BGP information.
It used to be less, currently it's about 1-5Mbit/second per server (anywhere
from 100-500GB data per month).
During certain times of the hour and the day the rate goes up significantly for a few seconds (basically to however many the CPU and the software can keep up with). 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.
- BGP access
- (only for anycast nodes) The NTP Pool DNS anycast AS number is 6647. It will be announced with the 'bird' daemon or with exabgp. The IPv4 prefix is 184.108.40.206/24. If you have IPv6, then we'll also announce 2620:101:d007::/48.
- The system needs incoming port 53 (duh), port 22 (or another port for ssh if you so require) and obviously port 179 to your routers for BGP. (No external firewall is needed, just in case you have one and it needs holes opened up. Be sure to disable session tracking for port 53/udp if you do have a firewall).
- We typically do the day-to-day management of the system.
If you are interested in helping with this, please email email@example.com.