user48786: It is said that addr message: Provide information on known nodes of the network. Non-advertised nodes should be forgotten after typically 3 hours.
I did not totally understood what does it mean forgetting a node? A node has a list of peers, and it is checking every 3 hours if these peer are active? Does it work like this? How does this forgetting mechanism work?

user48884: There is no need for a node to "forget" a node. This is not something that is required nor necessary. What Bitcoin Core does in response to a getaddr message (so it sends an addr message) is that it checks its list of nodes. It filters through that list for the things that it recently had a connection to and that it didn't have multiple failed connections to before. There is no checking that a node is actually live and it doesn't do it on a set timer either.

48786: <p>It is said that <em>addr message: Provide information on known nodes of the network. Non-advertised nodes should be forgotten after typically 3 hours.</em></p>

<p>I did not totally understood what does it mean forgetting a node? A node has a list of peers, and it is checking every 3 hours if these peer are active? Does it work like this? How does this forgetting mechanism work?</p>
 48884: <p>There is no need for a node to "forget" a node. This is not something that is required nor necessary. What Bitcoin Core does in response to a <code>getaddr</code> message (so it sends an <code>addr</code> message) is that it checks its list of nodes. It filters through that list for the things that it recently had a connection to and that it didn't have multiple failed connections to before. There is no checking that a node is actually live and it doesn't do it on a set timer either.</p>
