diff --git a/iroh-net/src/magic_endpoint.rs b/iroh-net/src/magic_endpoint.rs
index 6301fd695d..318ce5da92 100644
--- a/iroh-net/src/magic_endpoint.rs
+++ b/iroh-net/src/magic_endpoint.rs
@@ -405,6 +405,14 @@ impl MagicEndpoint {
     /// If addresses or relay servers are neither provided nor can be discovered, the connection
     /// attempt will fail with an error.
     pub async fn connect(&self, node_addr: NodeAddr, alpn: &[u8]) -> Result<quinn::Connection> {
+        // Connecting to ourselves is not supported.
+        if node_addr.node_id == self.node_id() {
+            bail!(
+                "Connecting to ourself is not supported ({} is the node id of this node)",
+                node_addr.node_id.fmt_short()
+            );
+        }
+
         if !node_addr.info.is_empty() {
             self.add_node_addr(node_addr.clone())?;
         }
@@ -501,6 +509,13 @@ impl MagicEndpoint {
     /// If no UDP addresses are added, and the given `relay_url` cannot be dialed, it will error.
     // TODO: This is infallible, stop returning a result.
     pub fn add_node_addr(&self, node_addr: NodeAddr) -> Result<()> {
+        // Connecting to ourselves is not supported.
+        if node_addr.node_id == self.node_id() {
+            bail!(
+                "Adding our own address is not supported ({} is the node id of this node)",
+                node_addr.node_id.fmt_short()
+            );
+        }
         self.msock.add_node_addr(node_addr);
         Ok(())
     }
@@ -620,6 +635,26 @@ mod tests {
         );
     }
 
+    #[tokio::test]
+    async fn test_connect_self() {
+        let _guard = iroh_test::logging::setup();
+        let ep = MagicEndpoint::builder()
+            .alpns(vec![TEST_ALPN.to_vec()])
+            .bind(0)
+            .await
+            .unwrap();
+        let my_addr = ep.my_addr().await.unwrap();
+        let res = ep.connect(my_addr.clone(), TEST_ALPN).await;
+        assert!(res.is_err());
+        let err = res.err().unwrap();
+        assert!(err.to_string().starts_with("Connecting to ourself"));
+
+        let res = ep.add_node_addr(my_addr);
+        assert!(res.is_err());
+        let err = res.err().unwrap();
+        assert!(err.to_string().starts_with("Adding our own address"));
+    }
+
     #[tokio::test]
     async fn magic_endpoint_connect_close() {
         let _guard = iroh_test::logging::setup();