Commit | Line | Data |
---|---|---|
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' |
11a5264b | 11 | # You'll need iproute-tc installed, for the tc command. |
1ccd5f67 JH |
12 | # You'll need kernel-modules-extra installed, or you get |
13 | # an unhelpful error from RTNETLINK. | |
14 | # To tidy up: 'sudo tc qdisc delete dev lo root' | |
a2673768 | 15 | # |
b536a578 JH |
16 | # MacOS: |
17 | # The kernel seems to have TFO enabled both ways as default. | |
18 | # There is a net.inet.tcp.clear_tfocache parameter | |
19 | ## sysctl -w foo-val | |
20 | # | |
21 | # For network delays there is something called 'Network Link Conditioner' | |
22 | # which might do the job. But how to manipulate it? | |
23 | # | |
24 | # | |
8255135b JH |
25 | sudo perl |
26 | system ("tc qdisc add dev lo root netem delay 50ms"); | |
27 | **** | |
28 | # | |
a2673768 JH |
29 | # First time runs will see a TFO request option only; subsequent |
30 | # ones should see the TFO cookie and fast-output SMTP banner | |
31 | # (currently on a separate packet after the server SYN,ACK but before | |
32 | # the client ACK). | |
33 | # | |
b536a578 JH |
34 | # The client log => line should have a "TFO" element. |
35 | # The server log <= line for a@test.ex should not. | |
ac0dcd3f | 36 | # |
b536a578 | 37 | # First clear any previously-obtained cookie: |
8255135b JH |
38 | sudo perl |
39 | system ("ip tcp_metrics delete 127.0.0.1"); | |
40 | **** | |
41 | # | |
a2673768 JH |
42 | # |
43 | # | |
44 | # FreeBSD: it looks like you have to compile a custom kernel, with | |
45 | # 'options TCP_RFC7413' in the config. Also set | |
46 | # 'net.inet.tcp.fastopen.enabled=1' in /etc/sysctl.conf | |
47 | # Untested. | |
48 | # | |
49 | exim -DSERVER=server -bd -oX PORT_D | |
50 | **** | |
ac0dcd3f | 51 | # |
a2673768 JH |
52 | exim a@test.ex |
53 | Testing | |
54 | **** | |
55 | sleep 3 | |
ac0dcd3f | 56 | # |
b536a578 JH |
57 | # The server log <= line for b@test.ex should have a "TFO" element, but |
58 | # this will only be obtained when the above delay is inserted into the | |
59 | # loopback net path. | |
60 | # | |
a2673768 JH |
61 | exim b@test.ex |
62 | Testing | |
63 | **** | |
64 | sleep 3 | |
ac0dcd3f | 65 | # |
8255135b JH |
66 | # |
67 | sudo perl | |
68 | system ("tc qdisc delete dev lo root"); | |
69 | **** | |
70 | # | |
a2673768 JH |
71 | killdaemon |
72 | no_msglog_check |