X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/ac0dcd3f05a8821d7ce042646472be1995a08042..8c513105fde2b8be3397216a0153f9b266fc7dfb:/test/scripts/1990-TCP-Fast-Open/1990

diff --git a/test/scripts/1990-TCP-Fast-Open/1990 b/test/scripts/1990-TCP-Fast-Open/1990
index cbedd3622..ec8e32c8f 100644
--- a/test/scripts/1990-TCP-Fast-Open/1990
+++ b/test/scripts/1990-TCP-Fast-Open/1990
@@ -7,19 +7,37 @@
 # 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'
+#
+# MacOS:
+# The kernel seems to have TFO enabled both ways as default.
+# There is a net.inet.tcp.clear_tfocache parameter
+## sysctl -w foo-val
+#
+# For network delays there is something called 'Network Link Conditioner'
+# which might do the job.  But how to manipulate it?
+#
+#
+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
 # (currently on a separate packet after the server SYN,ACK but before
 # the client ACK).
 #
-# The client log => lint.ex  should have a "TFO" element.
-# Assuming this is the first run since boot, the a@test recipient will not.
+# The client log => line  should have a "TFO" element.
+# The server log <= line for a@test.ex  should not.
 #
-# 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.
+# First clear any previously-obtained cookie:
+sudo perl
+system ("ip tcp_metrics delete 127.0.0.1");
+****
 #
 #
 #
@@ -36,10 +54,19 @@ Testing
 ****
 sleep 3
 #
+# 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.
+#
 exim b@test.ex
 Testing
 ****
 sleep 3
 #
+#
+sudo perl
+system ("tc qdisc delete dev lo root");
+****
+#
 killdaemon
 no_msglog_check