This is 0x21h.net
Some interesting resources here:
Stratum 2 NTP Server, Pool.Ntp.Org project participant
NTP Heat map for this server
Game servers:
- Counter Strike: Condition Zero - 0x21h.net:27024
- Counter Strike: Global Offensive - 0x21h.net:27018
- Counter Strike: Source - 0x21h.net:27021
- Counter Strike: 1.6 - 0x21h.net:27015
- Minecraft - 0x21h.net:25565
- Quake 3 - 0x21h.net:27960
- TeeWorlds - 0x21h.net:8303