What are seednodes?

Question

A follow up from a comment on this answer.

What are seednodes, and how do they differ from fallback nodes?

theymos · Accepted Answer · 2015-04-10T20:15:34.073

6

"Fallback nodes" is a page on the Bitcoin Wiki which lists some reliable Bitcoin nodes. "DNS Seeds" are DNS servers hard-coded into Bitcoin which return IP addresses of Bitcoin nodes which can be used for bootstrapping. "Seednodes" are Bitcoin nodes which have their IP addresses hard-coded into the Bitcoin client (see list here); they're used as an alternative bootstrapping method.

edited Apr 10 '15 at 20:15

answered May 17 '12 at 21:34

theymos

8,904
40
37

This link from your answer is (three years later) rotten. [Fixed link](https://github.com/bitcoin/bitcoin/blob/863e995b79ec388bf292d80f181912d01e20e2e5/src/net.cpp#L1198) (based on post date). – Gustavo Rodrigues Apr 10 '15 at 19:55

score 1 · Answer 2 · edited Apr 16 '13 at 16:32

DNS seeds aren't necessarily "seednodes" as they don't necessarily have have Bitcoin running as well. Instead these hosts have standard DNS servers with A records that new Bitcoin nodes use for bootstrapping to learn of peers.

Currently, Bitcoin master shows these four:

bitseed.xf2.org
dnsseed.bluematt.me
seed.bitcoin.sipa.be
dnsseed.bitcoin.dashjr.org

Source code:

https://github.com/bitcoin/bitcoin/blob/master/src/net.cpp#L1170

// DNS seeds
// Each pair gives a source name and a seed name.

// The first name is used as information source for addrman.
// The second name should resolve to a list of seed addresses.


static const char *strMainNetDNSSeed[][2] = {
    {"bitcoin.sipa.be", "seed.bitcoin.sipa.be"},
    {"bluematt.me", "dnsseed.bluematt.me"},
    {"dashjr.org", "dnsseed.bitcoin.dashjr.org"},
    {"xf2.org", "bitseed.xf2.org"},
    {NULL, NULL}
};

Those are DNS seeds. Seednodes are different. – theymos May 17 '12 at 21:35 — theymos, May 17 '12 at 21:35

What are seednodes?

2 Answers2

Linked