fix: resolve external ip on launch (#16768)

crates/net/discv4/src/lib.rs

@@ -252,7 +252,12 @@ impl Discv4 {
         local_node_record.udp_port = local_addr.port();
         trace!(target: "discv4", ?local_addr,"opened UDP socket");
 
-        let service = Discv4Service::new(socket, local_addr, local_node_record, secret_key, config);
+        let mut service =
+            Discv4Service::new(socket, local_addr, local_node_record, secret_key, config);
+
+        // resolve the external address immediately
+        service.resolve_external_ip();
+
         let discv4 = service.handle();
         Ok((discv4, service))
     }
@@ -620,6 +625,15 @@ impl Discv4Service {
         self.lookup_interval = tokio::time::interval(duration);
     }
 
+    /// Sets the external Ip to the configured external IP if [`NatResolver::ExternalIp`].
+    fn resolve_external_ip(&mut self) {
+        if let Some(r) = &self.resolve_external_ip_interval {
+            if let Some(external_ip) = r.resolver().as_external_ip() {
+                self.set_external_ip_addr(external_ip);
+            }
+        }
+    }
+
     /// Sets the given ip address as the node's external IP in the node record announced in
     /// discovery
     pub fn set_external_ip_addr(&mut self, external_ip: IpAddr) {

crates/net/nat/src/lib.rs

@@ -161,6 +161,11 @@ impl ResolveNatInterval {
         Self::with_interval(resolver, interval)
     }
 
+    /// Returns the resolver used by this interval
+    pub const fn resolver(&self) -> &NatResolver {
+        &self.resolver
+    }
+
     /// Completes when the next [`IpAddr`] in the interval has been reached.
     pub async fn tick(&mut self) -> Option<IpAddr> {
         poll_fn(|cx| self.poll_tick(cx)).await