diff --git a/src/buffer.rs b/src/buffer.rs
index 31b5bd6d..b1856c1a 100644
--- a/src/buffer.rs
+++ b/src/buffer.rs
@@ -148,6 +148,12 @@ impl ToBuf for &[u8] {
 #[allow(clippy::len_without_is_empty)]
 pub struct TmpBuf<'a>(&'a mut [u8], usize);
 
+impl core::fmt::Debug for TmpBuf<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("TmpBuf").field("data_len", &self.1).finish()
+    }
+}
+
 impl<'a> TmpBuf<'a> {
     /// Create a new temporary buffer from a mutable slice.
     pub fn new(buf: &'a mut [u8]) -> Self {
diff --git a/src/config.rs b/src/config.rs
index 7d7f551d..138155d5 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -15,7 +15,7 @@ use crate::crypto::rust_crypto;
 /// DTLS configuration shared by all connections.
 ///
 /// Build with [`Config::builder()`] or use [`Config::default()`].
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct Config {
     mtu: usize,
     max_queue_rx: usize,
@@ -201,6 +201,7 @@ impl Config {
 }
 
 /// Builder for [`Config`]. See each setter for defaults.
+#[derive(Debug)]
 pub struct ConfigBuilder {
     mtu: usize,
     max_queue_rx: usize,
diff --git a/src/lib.rs b/src/lib.rs
index 46adb1b1..0ae25e63 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -155,6 +155,7 @@
 #![warn(clippy::all)]
 #![allow(unknown_lints)]
 #![deny(missing_docs)]
+#![deny(missing_debug_implementations)]
 
 #[macro_use]
 extern crate log;