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linux:sysctl [2009/03/04 13:31] greebo |
linux:sysctl [2016/02/23 10:52] (current) zagi |
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====== Linux sysctl options ====== | ====== Linux sysctl options ====== | ||
- | |||
- | |||
Line 63: | Line 61: | ||
# | # | ||
# Do not send ICMP redirects (we are not a router) | # Do not send ICMP redirects (we are not a router) | ||
- | net/ | + | net/ |
# Do not accept IP source route packets (we are not a router) | # Do not accept IP source route packets (we are not a router) | ||
- | net/ | + | net/ |
# tcp/ip tweak - window size | # tcp/ip tweak - window size | ||
Line 88: | Line 86: | ||
net.ipv4.ipfrag_time = 30 | net.ipv4.ipfrag_time = 30 | ||
- | net.ipv4.tcp_ecn = 1 | + | net.ipv4.tcp_ecn = 0 |
net.ipv4.tcp_syncookies = 1 | net.ipv4.tcp_syncookies = 1 | ||
net.ipv4.tcp_timestamps = 1 | net.ipv4.tcp_timestamps = 1 | ||
+ | net.ipv4.tcp_sack = 1 | ||
# Linux 2.6 has only 32Mb shared memory | # Linux 2.6 has only 32Mb shared memory | ||
Line 99: | Line 98: | ||
# | # | ||
+ | |||
+ | # recommended for hosts with jumbo frames enabled | ||
+ | net.ipv4.tcp_mtu_probing=1 | ||
+ | |||
+ | net.ipv4.tcp_allowed_congestion_control = highspeed | ||
+ | net.ipv4.tcp_congestion_control = highspeed | ||
+ | |||
+ | net.ipv4.tcp_slow_start_after_idle=0 | ||
+ | |||
</ | </ | ||
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===== Misc add-on options on good to know bases ===== | ===== Misc add-on options on good to know bases ===== | ||
+ | |||
+ | ==== TCP "thin streams" | ||
+ | |||
+ | If you're using ssh logins over lossy networks (such as many mesh networks), you may be annoyed at the random delays you get after a loss event. | ||
+ | |||
+ | Linux 2.6.34 and later is able to use a more aggressive variant of TCP when a given TCP flow is detected as being " | ||
+ | aggressive TCP variant is only used with " | ||
+ | of connections. | ||
+ | |||
+ | This optimisation is enabled by putting the following in ''/ | ||
+ | |||
+ | | ||
+ | | ||
+ | |||
+ | Since it's a sender-only modification to TCP, the effect will be most dramatic if you do that on the client. | ||
+ | |||
+ | For more information, | ||
==== Reboot on kernel panic ==== | ==== Reboot on kernel panic ==== |