There is a overlap with this publish and others however I will attempt to instantly appropriate a few issues right here.
Why do now we have two kinds of connections, outgoing and incoming?
To threat stating the apparent generally our node will make a request to connect with one other node (outbound) while different occasions a node will make a request to connect with our node (inbound). In a wholesome peer to see (P2P) protocol you’ll be able to’t actually keep away from having each outgoing and incoming requests. The extent to which outbound and inbound connections are handled in another way by your full node is a extra fascinating query. These Bitcoin Core PR assessment membership notes (June eighth 2022) on inbound block-relay-only connections said:
As soon as the connection is established, the connection is basically symmetric (the protocol works the identical in each instructions), though we deal with outbound friends with some choice.
In case you are involved about malicious full nodes you might need some trusted or semi trusted full nodes you select to connect with (outbound) while presumably all inbound connection requests are from nodes you already know little or no about.
Are outgoing connections those the place we notify of latest blocks/transactions, whereas incoming connections are those the place they notify us of latest blocks/transactions?
No, each outbound and inbound connections can notify your node of latest blocks and transactions and vice versa. That PR assessment membership I referred to does talk about block-relay-only friends which is the place you determine to solely relay blocks to sure friends and never transactions, IP addresses. Inbound connections can even point out they do not need to obtain transactions and so forth.
After we do the preliminary synchronization (IBD) or utterly randomly need to ask a few block or transaction or one thing third, is it achieved with outgoing connections or incoming connections?
Each. If we aren’t conscious of any friends/connections (ie now we have no connections in any respect) initially of IBD we would have to make the most of DNS seeds to be taught of potential friends.
