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// Copy this file to /etc/bind/named.conf if you want to run bind as a
// recursive DNS resolver. If you want to run an authoritative nameserver
// instead, see /etc/bind/named.conf.authoritative.
//
// 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 {
// 123.123.123.123;
// 123.123.123.123;
//};
// 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;
};
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