Dnsmasq DNS DHCP Server

Dnsmasq is a free and open-source lightweight network infrastructure server that provides DNS forwarding, DNS caching, DHCP server, DHCP relay, and router advertisement (RA) services for small to medium-sized networks. Originally developed by Simon Kelley in 2001 and released under the GNU General Public License, Dnsmasq is designed to be lightweight, easy to configure, and suitable for resource-constrained environments like home routers, embedded devices, and virtual machines. Key features: DNS forwarding and caching: Dnsmasq forwards DNS queries to upstream recursive DNS servers (such as those provided by ISP or public resolvers like Cloudflare 1.1.1.1 and Google 8.8.8.8), caching responses to reduce latency and upstream load. The cache size is configurable (default 150 entries, expandable). DNS configuration: reads hostnames from /etc/hosts file to serve as local DNS records, enabling local hostname resolution without maintaining a separate zone file. DHCP server: full-featured DHCPv4 and DHCPv6 server supporting static IP address assignment via MAC address mapping, dynamic IP ranges, DHCP options (gateway, DNS server, NTP server, WINS server), multi-subnet DHCP, and PXE/tftp boot support for network booting. DHCP relay: relay DHCP requests between subnets. Router Advertisement: IPv6 Stateless Address Autoconfiguration (SLAAC) support via RA messages, enabling IPv6 address auto-configuration. DNSSEC validation: validates DNS responses using DNSSEC. DNS-over-TLS and DNS-over-HTTPS (DoT/DoH) support. Domain matching: route specific domains to specific upstream servers (e.g., corporate domains to internal DNS). PXE boot server: support for network boot via PXE protocol. Tag-based DHCP configuration for flexible host grouping. Cross-platform: Linux, macOS, BSD, Android (used in Android tethering). Used in OpenWrt, DD-WRT, and Tomato router firmware. GPL-2.0.