diff --git a/tools/testing/selftests/net/mptcp/mptcp_connect.sh b/tools/testing/selftests/net/mptcp/mptcp_connect.sh
index 5befd8584a4d..7a2a851fa0ad 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_connect.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_connect.sh
@@ -373,7 +373,7 @@ do_transfer()
 		fi
 
 		local capfile="${capprefix}-${connector_ns:0:3}-${listener_ns:0:3}-${cl_proto}-${srv_proto}-${connect_addr}-${port}"
-		local capopt="-i any -s 65535 -B 32768 ${capuser}"
+		local capopt="-i any -s 128 -B 32768 ${capuser}"
 
 		ip netns exec ${listener_ns} tcpdump ${capopt} \
 			-w "${capfile}-listener.pcap" >> "${capout}" 2>&1 &
diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 9b9fb3de9da3..18ce7136a2b0 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -979,7 +979,7 @@ cond_start_capture()
 		capfile=$(printf "mp_join-%02u-%s.pcap" "$MPTCP_LIB_TEST_COUNTER" "$ns")
 
 		echo "Capturing traffic for test $MPTCP_LIB_TEST_COUNTER into $capfile"
-		ip netns exec "$ns" tcpdump -i any -s 65535 -B 32768 $capuser -w "$capfile" > "$capout" 2>&1 &
+		ip netns exec "$ns" tcpdump -i any -s 128 -B 32768 $capuser -w "$capfile" > "$capout" 2>&1 &
 		cappid=$!
 
 		sleep 1
diff --git a/tools/testing/selftests/net/mptcp/simult_flows.sh b/tools/testing/selftests/net/mptcp/simult_flows.sh
index d723261bdc62..3ea3d1efe32e 100755
--- a/tools/testing/selftests/net/mptcp/simult_flows.sh
+++ b/tools/testing/selftests/net/mptcp/simult_flows.sh
@@ -149,7 +149,7 @@ do_transfer()
 		fi
 
 		local capfile="${capprefix}-${port}"
-		local capopt="-i any -s 65535 -B 32768 ${capuser}"
+		local capopt="-i any -s 108 -B 32768 ${capuser}"
 
 		ip netns exec ${ns3}  tcpdump ${capopt} -w "${capfile}-listener.pcap"  >> "${capout}" 2>&1 &
 		local cappid_listener=$!