X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/a2673768b71ee86c71e16e46d53d0ffc4f66b0de..c8b2f3749e953b254b4d6ac1ea047451eb771953:/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 47b77af0e..ec8e32c8f 100644
--- a/test/scripts/1990-TCP-Fast-Open/1990
+++ b/test/scripts/1990-TCP-Fast-Open/1990
@@ -7,17 +7,38 @@
 # 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 log <= line should have a "TFO" element.
+# The client log => line  should have a "TFO" element.
+# The server log <= line for a@test.ex  should not.
+#
+# First clear any previously-obtained cookie:
+sudo perl
+system ("ip tcp_metrics delete 127.0.0.1");
+****
 #
-# If the client-side is disabled in the kernel, Exim logs
-# will become noisy.
 #
 #
 # FreeBSD: it looks like you have to compile a custom kernel, with
@@ -27,13 +48,25 @@
 #
 exim -DSERVER=server -bd -oX PORT_D
 ****
+#
 exim a@test.ex
 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