// Copy this file to /etc/bind/named.conf.options if you want to run bind as a
// recursive DNS resolver. If you want to run an authoritative nameserver
// instead, see Ventz's "example-configs/authoritative/named.conf.options"
//
// BIND supports using the same daemon as both authoritative nameserver and
// recursive resolver; it supports this because it is the oldest and original
// nameserver and so was designed before it was realized that combining these
// functions is inadvisable.
//
// In actual fact, combining these functions is a very bad idea. It is thus
// recommended that you run a given instance of BIND as either an authoritative
// nameserver or recursive resolver, not both. The example configuration herein
// provides a starting point for running a recursive resolver.
//
//
// *** IMPORTANT ***
// You should note that running an open DNS resolver (that is, a resolver which
// answers queries from any globally routable IP) makes the resolver vulnerable
// to abuse in the form of reflected DDoS attacks.
//
// These attacks are now widely prevalent on the open internet. Even if
// unadvertised, attackers can and will find your resolver by portscanning the
// global IPv4 address space.
//
// In one case the traffic generated using such an attack reached 300 Gb/s (!).
//
// It is therefore imperative that you take care to configure the resolver to
// only answer queries from IP address space you trust or control. See the
// "allow-recursion" directive below.
//
// Bear in mind that with these attacks, the "source" of a query will actually
// be the intended target of a DDoS attack, so this only protects other networks
// from attack, not your own; ideally therefore you should firewall DNS traffic
// at the borders of your network to eliminate spoofed traffic.
//
// This is a complex issue and some level of understanding of these attacks is
// advisable before you attempt to configure a resolver.

options {
	directory "/var/bind";

	// Specify a list of CIDR masks which should be allowed to issue recursive
	// queries to the DNS server. Do NOT specify 0.0.0.0/0 here; see above.
	allow-recursion {
		127.0.0.1/32;
	};

	// If you want this resolver to itself resolve via means of another recursive
	// resolver, uncomment this block and specify the IP addresses of the desired
	// upstream resolvers.
	//forwarders {
	//	8.8.8.8;
	//	8.8.4.4;
	//};

	// By default the resolver will attempt to perform recursive resolution itself
	// if the forwarders are unavailable. If you want this resolver to fail outright
	// if the upstream resolvers are unavailable, uncomment this directive.
	//forward only;

	// Configure the IPs to listen on here.
	listen-on { 127.0.0.1; };
	listen-on-v6 { none; };

	// If you have problems and are behind a firewall:
	//query-source address * port 53;

	pid-file "/var/run/named/named.pid";

	// Removing this block will cause BIND to revert to its default behaviour
	// of allowing zone transfers to any host (!). There is no need to allow zone
	// transfers when operating as a recursive resolver.
	allow-transfer { none; };
};

// Briefly, a zone which has been declared delegation-only will be effectively
// limited to containing NS RRs for subdomains, but no actual data beyond its
// own apex (for example, its SOA RR and apex NS RRset). This can be used to
// filter out "wildcard" or "synthesized" data from NAT boxes or from
// authoritative name servers whose undelegated (in-zone) data is of no
// interest.
// See http://www.isc.org/products/BIND/delegation-only.html for more info

//zone "COM" { type delegation-only; };
//zone "NET" { type delegation-only; };

zone "." IN {
	type hint;
	file "named.ca";
};

zone "localhost" IN {
	type master;
	file "pri/localhost.zone";
	allow-update { none; };
	notify no;
};

zone "127.in-addr.arpa" IN {
	type master;
	file "pri/127.zone";
	allow-update { none; };
	notify no;
};