Dnsmasq

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Dnsmasq

Developer:	Simon Kelley
Latest release:	2.38 / February 12, 2007
OS:	Unix-like
Use:	DNS server
License:	GNU General Public License
Website:	thekelleys.org.uk/dnsmasq/

Dnsmasq is a lightweight, easy to configure, DNS forwarder and DHCP server. It is designed to provide DNS and optionally, DHCP, to a small network. It can serve the names of local machines which are not in the global DNS. The DHCP server integrates with the DNS server and allows machines with DHCP-allocated addresses to appear in the DNS with names configured either in each host or in a central configuration file. Dnsmasq supports static and dynamic DHCP leases and BOOTP for network booting of diskless machines.

Dnsmasq is targeted at home networks using NAT and connected to the internet via a modem, cable-modem or ADSL connection but would be a good choice for any small network where low resource use and ease of configuration are important.

Supported platforms include Linux (with glibc and uclibc), *BSD and Mac OS X. Dnsmasq is included in at least the following Linux distributions: Ubuntu, Gentoo, Debian, Slackware, SUSE, Smoothwall, IP-Cop, floppyfw, Firebox, LEAF, FREESCO, fli4l, CoyoteLinux and Clarkconnect. It is also available as a FreeBSD port and is used in Linksys wireless routers and the m0n0wall and related pfsense projects.

Dnsmasq provides the following features:

The DNS configuration of machines behind the firewall is simple and doesn't depend on the details of the ISP's DNS servers
Clients which try to do DNS lookups while a modem link to the internet is down will time out immediately.
Dnsmasq will serve names from the /etc/hosts file (or an alternate). If the names of local machines are there, then they can all be addressed without having to maintain /etc/hosts on each machine.
The integrated DHCP server supports static and dynamic DHCP leases and multiple networks and IP ranges. It works across BOOTP relays and supports DHCP options including RFC 3397 DNS search lists.
Machines which are configured by DHCP have their names automatically included in the DNS and the names can specified by each machine or centrally by associating a name with a MAC address in the dnsmasq config file.
Dnsmasq caches internet addresses (A records and AAAA records) and address-to-name mappings (PTR records), reducing the load on upstream servers and improving performance (especially on modem connections).
Dnsmasq can be configured to automatically pick up the addresses of its upstream nameservers from ppp or dhcp configuration. It will automatically reload this information if it changes. This facility will be of particular interest to maintainers of Linux firewall distributions since it allows dns configuration to be made automatic.
On IPv6-enabled boxes, dnsmasq can both talk to upstream servers via IPv6 and offer DNS service via IPv6. On dual-stack (IPv4 and IPv6) boxes it talks both protocols and can even act as IPv6-to-IPv4 or IPv4-to-IPv6 forwarder.
Dnsmasq can be configured to send queries for certain domains to upstream servers handling only those domains. This makes integration with private DNS systems easy.
Dnsmasq supports MX records and can be configured to return MX records for any or all local machines.