diff --git a/src/handler/request_call.rs b/src/handler/request_call.rs
index b91c7643e..68233c474 100644
--- a/src/handler/request_call.rs
+++ b/src/handler/request_call.rs
@@ -1,4 +1,4 @@
-pub use crate::node_info::{NodeAddress, NodeContact};
+pub use crate::node_info::{NodeContact};
 use crate::{
     packet::Packet,
     rpc::{Request, RequestBody},
diff --git a/src/kbucket/entry.rs b/src/kbucket/entry.rs
index 1e0304048..7df9429af 100644
--- a/src/kbucket/entry.rs
+++ b/src/kbucket/entry.rs
@@ -26,7 +26,7 @@
 
 pub use super::{
     bucket::{
-        AppliedPending, ConnectionState, InsertResult, Node, NodeStatus, MAX_NODES_PER_BUCKET,
+        AppliedPending, ConnectionState, InsertResult, Node, NodeStatus,
     },
     key::*,
     ConnectionDirection,
diff --git a/src/packet/mod.rs b/src/packet/mod.rs
index f071263bd..ef7ad63c0 100644
--- a/src/packet/mod.rs
+++ b/src/packet/mod.rs
@@ -29,16 +29,25 @@ pub const MESSAGE_NONCE_LENGTH: usize = 12;
 /// The Id nonce length (in bytes).
 pub const ID_NONCE_LENGTH: usize = 16;
 
+pub struct Nat;
+
+impl ProtocolIdentity<3> for Nat {
+    const PROTOCOL_ID_BYTES: [u8; 6] = *b"discv5";
+    const PROTOCOL_VERSION_BYTES: [u8; 2] = 0x0001_u16.to_be_bytes();
+    const IMPLEMENTATION_FEATURES: [u8; 3] = *b"nat";
+}
 pub struct DefaultProtocolId {}
 
 impl ProtocolIdentity for DefaultProtocolId {
     const PROTOCOL_ID_BYTES: [u8; 6] = *b"discv5";
     const PROTOCOL_VERSION_BYTES: [u8; 2] = 0x0001_u16.to_be_bytes();
+    const IMPLEMENTATION_FEATURES: [u8; 0] = *b"";
 }
 
-pub trait ProtocolIdentity {
+pub trait ProtocolIdentity<const N: usize = 0>: Sync + Send {
     const PROTOCOL_ID_BYTES: [u8; 6];
     const PROTOCOL_VERSION_BYTES: [u8; 2];
+    const IMPLEMENTATION_FEATURES: [u8; N];
 }
 
 pub(crate) const MAX_PACKET_SIZE: usize = 1280;