A new Radix node contacts one or more seed nodes to get a list of other nodes on the network when it starts up. If the node is unable to connect to one of the official Radix seed nodes, then the node will stall.
The seed node is specified in the default.config file under the network.p2p.seed_nodes key
network.p2p.seed_nodes=radix://rn1qvw5v4w8llexz99uc9gmeh47qp2h9ax2y3aewm5e6vj5sdx8uuph2vfuvg3@3.221.232.135
It is possible to specify multiple seed nodes by separating them with a comma:
network.p2p.seed_nodes=radix://rn1qvw5v4w8llexz99uc9gmeh47qp2h9ax2y3aewm5e6vj5sdx8uuph2vfuvg3@3.221.232.135,radix://rn1qtq336a2nn2269fjes53pynwlytrv0katm6uzlfcyl6m7yscac5g7mh8prw@3.220.101.80,radix://rn1qwa45jjf40vuf9xlq85xym86yegnm95h3g8d4lul5hskrws9gm6ykyx7hsf@3.214.160.245
The good news is that any node on the Radix network can act as a seed node - as long as you know the IP address of the node and node address (rdx1…).
Seed nodes have the following URI format:
radix://rn1....@ip.address
The rn1... part is the Radix Node Address that is used during the Radix node handshake protocol to created a shared secret for encrypted communication between the two nodes.
Convert the Validator Address into a Node Address: How to convert a Validator Address (rv...) into a Node Address (rn...)
See also: What community archive nodes can I use with the Radix Desktop Wallet?