Commit | Line | Data |
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a2673768 JH |
1 | # TCP Fast Open |
2 | # | |
3 | # Linux: | |
4 | # Both server and client-side TFO support must be enabled in the | |
5 | # kernel, 'sudo sh -c "echo 3 > /proc/sys/net/ipv4/tcp_fastopen"'. | |
6 | # | |
7 | # A packet capture on the loopback interface will show the TFO | |
8 | # option on the SYN, but the fast-output SMTP banner will not | |
9 | # be seen unless you also deliberately emulate a long path: | |
8255135b | 10 | # 'sudo tc qdisc add dev lo root netem delay 50ms' |
1ccd5f67 JH |
11 | # You'll need kernel-modules-extra installed, or you get |
12 | # an unhelpful error from RTNETLINK. | |
13 | # To tidy up: 'sudo tc qdisc delete dev lo root' | |
a2673768 | 14 | # |
8255135b JH |
15 | sudo perl |
16 | system ("tc qdisc add dev lo root netem delay 50ms"); | |
17 | **** | |
18 | # | |
a2673768 JH |
19 | # First time runs will see a TFO request option only; subsequent |
20 | # ones should see the TFO cookie and fast-output SMTP banner | |
21 | # (currently on a separate packet after the server SYN,ACK but before | |
22 | # the client ACK). | |
23 | # | |
ac0dcd3f JH |
24 | # The client log => lint.ex should have a "TFO" element. |
25 | # Assuming this is the first run since boot, the a@test recipient will not. | |
26 | # | |
8255135b JH |
27 | sudo perl |
28 | system ("ip tcp_metrics delete 127.0.0.1"); | |
29 | **** | |
30 | # | |
ac0dcd3f JH |
31 | # The server log <= line for b@test.ex should have a "TFO" element, but |
32 | # this will only be obtained when the above delay is inserted into the | |
33 | # loopback net path. | |
a2673768 | 34 | # |
a2673768 JH |
35 | # |
36 | # | |
37 | # FreeBSD: it looks like you have to compile a custom kernel, with | |
38 | # 'options TCP_RFC7413' in the config. Also set | |
39 | # 'net.inet.tcp.fastopen.enabled=1' in /etc/sysctl.conf | |
40 | # Untested. | |
41 | # | |
42 | exim -DSERVER=server -bd -oX PORT_D | |
43 | **** | |
ac0dcd3f | 44 | # |
a2673768 JH |
45 | exim a@test.ex |
46 | Testing | |
47 | **** | |
48 | sleep 3 | |
ac0dcd3f | 49 | # |
a2673768 JH |
50 | exim b@test.ex |
51 | Testing | |
52 | **** | |
53 | sleep 3 | |
ac0dcd3f | 54 | # |
8255135b JH |
55 | # |
56 | sudo perl | |
57 | system ("tc qdisc delete dev lo root"); | |
58 | **** | |
59 | # | |
a2673768 JH |
60 | killdaemon |
61 | no_msglog_check |