# A packet capture on the loopback interface will show the TFO
# option on the SYN, but the fast-output SMTP banner will not
# be seen unless you also deliberately emulate a long path:
-# 'sudo tc qdisc add dev lo root netem delay 100ms'
+# 'sudo tc qdisc add dev lo root netem delay 50ms'
+# You'll need iproute-tc installed, for the tc command.
+# You'll need kernel-modules-extra installed, or you get
+# an unhelpful error from RTNETLINK.
+# To tidy up: 'sudo tc qdisc delete dev lo root'
+#
+sudo perl
+system ("tc qdisc add dev lo root netem delay 50ms");
+****
#
# First time runs will see a TFO request option only; subsequent
# ones should see the TFO cookie and fast-output SMTP banner
# The client log => lint.ex should have a "TFO" element.
# Assuming this is the first run since boot, the a@test recipient will not.
#
+sudo perl
+system ("ip tcp_metrics delete 127.0.0.1");
+****
+#
# The server log <= line for b@test.ex should have a "TFO" element, but
# this will only be obtained when the above delay is inserted into the
# loopback net path.
****
sleep 3
#
+#
+sudo perl
+system ("tc qdisc delete dev lo root");
+****
+#
killdaemon
no_msglog_check