--dhcp-no-override

(IPv4 only) Disable re-use of the DHCP servername and filename fields as extra option space. If it can, dnsmasq moves the boot server and filename information (from --dhcp-boot) out of their dedicated fields into DHCP options. This make extra space available in the DHCP packet for options but can, rarely, confuse old or broken clients. This flag forces "simple and safe" behaviour to avoid problems in such a case.