1  Expectations for DNS Seed operators
 2  ====================================
 3  
 4  Bitcoin Core attempts to minimize the level of trust in DNS seeds,
 5  but DNS seeds still pose a small amount of risk for the network.
 6  As such, DNS seeds must be run by entities which have some minimum
 7  level of trust within the Bitcoin community.
 8  
 9  Other implementations of Bitcoin software may also use the same
10  seeds and may be more exposed. In light of this exposure, this
11  document establishes some basic expectations for operating dnsseeds.
12  
13  0. A DNS seed operating organization or person is expected to follow good
14  host security practices, maintain control of applicable infrastructure,
15  and not sell or transfer control of the DNS seed. Any hosting services
16  contracted by the operator are equally expected to uphold these expectations.
17  
18  1. The DNS seed results must consist exclusively of fairly selected and
19  functioning Bitcoin nodes from the public network to the best of the
20  operator's understanding and capability.
21  
22  2. For the avoidance of doubt, the results may be randomized but must not
23  single-out any group of hosts to receive different results unless due to an
24  urgent technical necessity and disclosed.
25  
26  3. The results may not be served with a DNS TTL of less than one minute.
27  
28  4. Any logging of DNS queries should be only that which is necessary
29  for the operation of the service or urgent health of the Bitcoin
30  network and must not be retained longer than necessary nor disclosed
31  to any third party.
32  
33  5. Information gathered as a result of the operators node-spidering
34  (not from DNS queries) may be freely published or retained, but only
35  if this data was not made more complete by biasing node connectivity
36  (a violation of expectation (1)).
37  
38  6. Operators are encouraged, but not required, to publicly document the
39  details of their operating practices.
40  
41  7. A reachable email contact address must be published for inquiries
42  related to the DNS seed operation.
43  
44  If these expectations cannot be satisfied the operator should
45  discontinue providing services and contact the active Bitcoin
46  Core development team as well as posting on
47  [bitcoin-dev](https://groups.google.com/g/bitcoindev).
48  
49  Behavior outside of these expectations may be reasonable in some
50  situations but should be discussed in public in advance.
51  
52  See also
53  ----------
54  - [bitcoin-seeder](https://github.com/sipa/bitcoin-seeder) is a reference implementation of a DNS seed.