We are running a substrate private blockchain network. We are able to add a total of 8 nodes but are not able to increase more than that.

For the 9th node: 9th node is not starting to sync after performing node authorization. So here I am trying to understand do we have any limit in the no of connecting nodes in Substrate private network.

And Is there a way we can increase the no of nodes in the same network?

Thanks in Advance

  • is there any error you are facing while adding the 9th node? Commented Feb 27, 2023 at 8:58
  • @ImmanuelJohn There are no errors, but node sync is not happening for the 9th node. I could find some suggestions like adding max-peers flag to the configuration but not able to identify the exact file to update this flag.
    – Anbu
    Commented Feb 27, 2023 at 9:18
  • Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.
    – Community Bot
    Commented Feb 27, 2023 at 10:30
  • You can trying using the --in-peers and --out-peers flags to set the desired peers count.
    – pepoviola
    Commented Apr 23, 2023 at 13:53

2 Answers 2


Did you use auto-discovery?

I encountered this before, but I'm not sure if they were caused by the same reason.


  1. setting up a bootnode and use --bootnodes
  2. manually setting up the --port for each of them

If you are using the pallet_node_authorization then the default limit is 8 which is set in the runtime config. You can increase/update this number accordingly. I have set this to 512 in the below example.

    parameter_types! {
        pub const MaxWellKnownNodes: u32 = 512;
        pub const MaxPeerIdLength: u32 = 128;
    impl pallet_node_authorization::Config for Runtime {
        type Event = Event;
        type MaxWellKnownNodes = MaxWellKnownNodes;
        type MaxPeerIdLength = MaxPeerIdLength;
        type AddOrigin = EnsureRoot<AccountId>;
        type RemoveOrigin = EnsureRoot<AccountId>;
        type SwapOrigin = EnsureRoot<AccountId>;
        type ResetOrigin = EnsureRoot<AccountId>;
        type WeightInfo = ();

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