We find SimpleDNSPlus (https://simpledns.plus<https://simpledns.plus/>) scales quite well. It runs under windows, but as long as you operated behind a good firewall, it’s not a security issue. It also can host zones as well, so can double as a recursive name server and as a primary or secondary name server for your hosted domains. It includes a nice graphical display of performance metrics. -mel via cell On Aug 7, 2025, at 5:45 PM, DurgaPrasad - DatasoftComnet via NANOG <nanog@lists.nanog.org> wrote: Hello all, Do you have any recommendations for recursive DNS servers for a medium sized (20-30k users) ISP. We have used powerdns and unbound but sometimes find the caching times a bit on upper side. Any suggestions between these two or anything new? Also need points on how much we tune the settings pros and cons if any. Thank you /DP _______________________________________________ NANOG mailing list https://lists.nanog.org/archives/list/nanog@lists.nanog.org/message/SUTKDISS...