Parece ser uma opção de tempo de compilação para o dnsmasq.
Veja dnsmasq-discuss link .
There are timeouts in dnsmasq too, which are only changeable by re-compiling. Under very heavy load, dnsmasq will only hold onto a query for 10 seconds. It always drops unanswered queries after 4 times that (ie 40 seconds.) This is set in src/config.h