diff --git a/neqo-common/src/datagram.rs b/neqo-common/src/datagram.rs
index 9cebb64ea5..cc2cb7d113 100644
--- a/neqo-common/src/datagram.rs
+++ b/neqo-common/src/datagram.rs
@@ -53,6 +53,10 @@ impl Datagram {
     pub fn ttl(&self) -> Option<u8> {
         self.ttl
     }
+
+    pub fn set_tos(&mut self, tos: IpTos) {
+        self.tos = tos;
+    }
 }
 
 impl Deref for Datagram {
@@ -90,8 +94,7 @@ use test_fixture::datagram;
 fn fmt_datagram() {
     let d = datagram([0; 1].to_vec());
     assert_eq!(
-        format!("{d:?}"),
+        &format!("{d:?}"),
         "Datagram IpTos(Cs0, NotEct) TTL Some(128) [fe80::1]:443->[fe80::1]:443: [1]: 00"
-            .to_string()
     );
 }
diff --git a/neqo-common/src/tos.rs b/neqo-common/src/tos.rs
index 3610f72750..533c5447e2 100644
--- a/neqo-common/src/tos.rs
+++ b/neqo-common/src/tos.rs
@@ -36,7 +36,7 @@ impl From<IpTosEcn> for u8 {
 
 impl From<u8> for IpTosEcn {
     fn from(v: u8) -> Self {
-        match v & 0b11 {
+        match v & 0b0000_0011 {
             0b00 => IpTosEcn::NotEct,
             0b01 => IpTosEcn::Ect1,
             0b10 => IpTosEcn::Ect0,
@@ -47,8 +47,8 @@ impl From<u8> for IpTosEcn {
 }
 
 impl From<IpTos> for IpTosEcn {
-    fn from(value: IpTos) -> Self {
-        IpTosEcn::from(value.0 & 0x3)
+    fn from(v: IpTos) -> Self {
+        IpTosEcn::from(u8::from(v))
     }
 }
 
@@ -166,14 +166,13 @@ impl From<u8> for IpTosDscp {
 }
 
 impl From<IpTos> for IpTosDscp {
-    fn from(value: IpTos) -> Self {
-        IpTosDscp::from(value.0 & 0xfc)
+    fn from(v: IpTos) -> Self {
+        IpTosDscp::from(u8::from(v))
     }
 }
 
 /// The type-of-service field in an IP packet.
-#[allow(clippy::module_name_repetitions)]
-#[derive(Copy, Clone, PartialEq, Eq)]
+#[derive(Copy, Clone, PartialEq, Eq, Default)]
 pub struct IpTos(u8);
 
 impl From<IpTosEcn> for IpTos {
@@ -215,15 +214,19 @@ impl From<u8> for IpTos {
 impl Debug for IpTos {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         f.debug_tuple("IpTos")
-            .field(&IpTosDscp::from(self.0 & 0xfc))
-            .field(&IpTosEcn::from(self.0 & 0x3))
+            .field(&IpTosDscp::from(*self))
+            .field(&IpTosEcn::from(*self))
             .finish()
     }
 }
 
-impl Default for IpTos {
-    fn default() -> Self {
-        (IpTosDscp::default(), IpTosEcn::default()).into()
+impl IpTos {
+    pub fn set_ecn(&mut self, ecn: IpTosEcn) {
+        self.0 = u8::from(IpTosDscp::from(*self)) | u8::from(ecn);
+    }
+
+    pub fn set_dscp(&mut self, dscp: IpTosDscp) {
+        self.0 = u8::from(IpTosEcn::from(*self)) | u8::from(dscp);
     }
 }
 
@@ -322,4 +325,25 @@ mod tests {
         assert_eq!(tos, u8::from(iptos));
         assert_eq!(IpTos::from(tos), iptos);
     }
+
+    #[test]
+    fn iptos_to_iptosdscp() {
+        let tos = IpTos::from((IpTosDscp::Af41, IpTosEcn::NotEct));
+        let dscp = IpTosDscp::from(tos);
+        assert_eq!(dscp, IpTosDscp::Af41);
+    }
+
+    #[test]
+    fn tos_modify_ecn() {
+        let mut iptos: IpTos = (IpTosDscp::Af41, IpTosEcn::NotEct).into();
+        iptos.set_ecn(IpTosEcn::Ce);
+        assert_eq!(u8::from(iptos), 0b1000_1011);
+    }
+
+    #[test]
+    fn tos_modify_dscp() {
+        let mut iptos: IpTos = (IpTosDscp::Af41, IpTosEcn::Ect1).into();
+        iptos.set_dscp(IpTosDscp::Le);
+        assert_eq!(u8::from(iptos), 0b0000_0101);
+    }
 }
diff --git a/neqo-transport/src/connection/dump.rs b/neqo-transport/src/connection/dump.rs
index 34ac58f55e..12d337c570 100644
--- a/neqo-transport/src/connection/dump.rs
+++ b/neqo-transport/src/connection/dump.rs
@@ -9,7 +9,7 @@
 
 use std::fmt::Write;
 
-use neqo_common::{qdebug, Decoder};
+use neqo_common::{qdebug, Decoder, IpTos};
 
 use crate::{
     connection::Connection,
@@ -26,6 +26,7 @@ pub fn dump_packet(
     pt: PacketType,
     pn: PacketNumber,
     payload: &[u8],
+    tos: IpTos,
 ) {
     if log::STATIC_MAX_LEVEL == log::LevelFilter::Off || !log::log_enabled!(log::Level::Debug) {
         return;
@@ -43,5 +44,13 @@ pub fn dump_packet(
             write!(&mut s, "\n  {} {}", dir, &x).unwrap();
         }
     }
-    qdebug!([conn], "pn={} type={:?} {}{}", pn, pt, path.borrow(), s);
+    qdebug!(
+        [conn],
+        "pn={} type={:?} {} {:?}{}",
+        pn,
+        pt,
+        path.borrow(),
+        tos,
+        s
+    );
 }
diff --git a/neqo-transport/src/connection/mod.rs b/neqo-transport/src/connection/mod.rs
index 75c3490cba..535d3f4084 100644
--- a/neqo-transport/src/connection/mod.rs
+++ b/neqo-transport/src/connection/mod.rs
@@ -19,7 +19,7 @@ use std::{
 
 use neqo_common::{
     event::Provider as EventProvider, hex, hex_snip_middle, hrtime, qdebug, qerror, qinfo,
-    qlog::NeqoQlog, qtrace, qwarn, Datagram, Decoder, Encoder, Role,
+    qlog::NeqoQlog, qtrace, qwarn, Datagram, Decoder, Encoder, IpTos, Role,
 };
 use neqo_crypto::{
     agent::CertificateInfo, Agent, AntiReplay, AuthenticationStatus, Cipher, Client, Group,
@@ -1492,6 +1492,7 @@ impl Connection {
                         payload.packet_type(),
                         payload.pn(),
                         &payload[..],
+                        d.tos(),
                     );
 
                     qlog::packet_received(&mut self.qlog, &packet, &payload);
@@ -2255,6 +2256,7 @@ impl Connection {
                 pt,
                 pn,
                 &builder.as_ref()[payload_start..],
+                IpTos::default(), // TODO: set from path
             );
             qlog::packet_sent(
                 &mut self.qlog,