diff --git a/repos/os/src/server/nic_router/dhcp_client.cc b/repos/os/src/server/nic_router/dhcp_client.cc
index e74cbebcc6..340fa28313 100644
--- a/repos/os/src/server/nic_router/dhcp_client.cc
+++ b/repos/os/src/server/nic_router/dhcp_client.cc
@@ -193,6 +193,7 @@ void Dhcp_client::_send(Message_type msg_type,
 		ip.header_length(sizeof(Ipv4_packet) / 4);
 		ip.version(4);
 		ip.diff_service(0);
+		ip.ecn(0);
 		ip.identification(0);
 		ip.flags(0);
 		ip.fragment_offset(0);
diff --git a/repos/os/src/server/nic_router/interface.cc b/repos/os/src/server/nic_router/interface.cc
index 83173c3676..87e5d8e0d5 100644
--- a/repos/os/src/server/nic_router/interface.cc
+++ b/repos/os/src/server/nic_router/interface.cc
@@ -452,6 +452,7 @@ void Interface::_send_dhcp_reply(Dhcp_server               const &dhcp_srv,
 		ip.header_length(sizeof(Ipv4_packet) / 4);
 		ip.version(4);
 		ip.diff_service(0);
+		ip.ecn(0);
 		ip.identification(0);
 		ip.flags(0);
 		ip.fragment_offset(0);