I am tinkering with the bitcoin source code and trying to understand the exact working of peer discovery mechanism in the testnet mode for which I have made the following changes:

  1. Disabled the DNS seed discovery in order to force bitcoind to fallback to connect to hardcoded nodes.

  2. Changed the default hardcoded nodes to my known 4 addresses, lets say A,B,C and D, which I ensure are always online.

Now, when I run the bitcoind client (call it E), it connects to one of A,B,C or D, running the same modified version of bitcoind. It gets the peer addresses from the hardcoded node that it first connects to by exchanging getaddr and addr messages but I am not sure how it proceeds after that. I have following queries:

a. If a node falls back to connect to hardcoded nodes, is it supposed to connect to only one of the hardcoded nodes like it happends in my case or can it connect to multiple hardcoded nodes ?

b. After getting peer address via the addr message, when will the node E start connecting to those peers ?

Please point me to the relevant code files/sections if possible. Thanks

  • Have you read bitcoin.stackexchange.com/questions/3536/… ? Are you looking for more specific information about what happens after connecting to a hardcoded node?
    – Nick ODell
    Oct 28, 2015 at 3:02
  • @NickODell yes I read that already on the bitcoin wiki page. I am looking for 2 specific things: a) Let us say there are 4 hardcoded nodes that are online, then my node E connects to exactly one of them. Why does it not connect to more than 1 hardcoded nodes ? Is that the correct intended behaviour of bitcoin ? b) After the hardcoded node informs node E about presence of other nodes on the network and node E stores that in peers.dat, when will it start connecting to those nodes, because right now in my case it seems to be doing nothing with those nodes. Oct 28, 2015 at 3:35

1 Answer 1


Did you add the hardcoded nodes with addnode or with connect?

addnode=<ip> Add a node to connect to and attempt to keep the connection open
connect=<ip> Connect only to the specified node(s)

So, if you used connect, it will not connect to any but the hardcoded nodes.

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