1 # TLS client: TLS setup fails - retry in clear (with fastopen)
3 # If all works you'll not see any difference. To enable in the
4 # kernel, 'sudo sh -c "echo 3 > /proc/sys/net/ipv4/tcp_fastopen"'.
5 # A packet capture on the loopback interface will show the TFU
6 # option on the SYN, but the fast-output SMTP banner will not
7 # be seen unless you also deliberately emulate a long path:
8 # 'sudo tc qdisc add dev lo root netem delay 100ms'
10 # If the client-side is disabled in the kernel, Exim logs
14 exim -DSERVER=server -bd -oX PORT_D