Currently, dnslog.cn have short sessions (around half an hour). There should be way to prolong the sesion to how long the scan takes. Also, sometimes DNS query happens much later than request received. Someone reported got DNS request hours after the request has been made.
As workaround, nmap NSE scripts retrieve session after each host scanned.
Therefore, currently, for best assurance it is to use custom DNS domain with tool like logdns:
https://github.com/kost/logdns
Currently, dnslog.cn have short sessions (around half an hour). There should be way to prolong the sesion to how long the scan takes. Also, sometimes DNS query happens much later than request received. Someone reported got DNS request hours after the request has been made.
As workaround, nmap NSE scripts retrieve session after each host scanned.
Therefore, currently, for best assurance it is to use custom DNS domain with tool like logdns: https://github.com/kost/logdns