X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/38da9088282b3a74ddcbfe8d60382b55a7e9f426..f078f86ef3e6d0119845cdf8603b8174770cacc7:/test/scripts/4027-TFO-socks/4027

diff --git a/test/scripts/4027-TFO-socks/4027 b/test/scripts/4027-TFO-socks/4027
index 44d177ac5..a7412aecd 100644
--- a/test/scripts/4027-TFO-socks/4027
+++ b/test/scripts/4027-TFO-socks/4027
@@ -1,5 +1,8 @@
 # socks5 proxy on smtp transport, TCP Fast Open
 #
+# NOTE: ensure that TFO is fully enabled in the kernel.
+# For linux: sysctl net.ipv4.tcp_fastopen=3
+# 
 munge loopback
 #
 #
@@ -7,7 +10,7 @@ munge loopback
 # Disable TFO blackhole-detection as we seem to be running afoul of that
 sudo perl
 system ("ip tcp_metrics delete 127.0.0.1");
-system ("echo 0 > /proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_sec");
+system ("[ -e /proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_sec ] && echo 0 > /proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_sec");
 ****
 #
 # TFO both clients and server, no cookie yet
@@ -127,7 +130,7 @@ quit
 millisleep 500
 #
 sudo perl
-system ("echo 3600 > /proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_sec");
+system ("[ -e /proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_sec ] && echo 3600 > /proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_sec");
 ****
 #
 # Ends