sysctl

1sysctl(选项)(参数)

1-n：打印值时不打印关键字；
2-e：忽略未知关键字错误；
3-N：仅打印名称；
4-w：当改变sysctl设置时使用此项；
5-p：从配置文件“/etc/sysctl.conf”加载内核参数设置；
6-a：打印当前所有可用的内核参数变量和值；
7-A：以表格方式打印当前所有可用的内核参数变量和值。

1sysctl kern.maxfiles=5000
2kern.maxfiles: 2088 -> 5000

 1sysctl -w kernel.sysrq=0
 2sysctl -w kernel.core_uses_pid=1
 3sysctl -w net.ipv4.conf.default.accept_redirects=0
 4sysctl -w net.ipv4.conf.default.accept_source_route=0
 5sysctl -w net.ipv4.conf.default.rp_filter=1
 6sysctl -w net.ipv4.tcp_syncookies=1
 7sysctl -w net.ipv4.tcp_max_syn_backlog=2048
 8sysctl -w net.ipv4.tcp_fin_timeout=30
 9sysctl -w net.ipv4.tcp_synack_retries=2
10sysctl -w net.ipv4.tcp_keepalive_time=3600
11sysctl -w net.ipv4.tcp_window_scaling=1
12sysctl -w net.ipv4.tcp_sack=1

 1# Controls source route verification
 2# Default should work for all interfaces
 3net.ipv4.conf.default.rp_filter = 1
 4# net.ipv4.conf.all.rp_filter = 1
 5# net.ipv4.conf.lo.rp_filter = 1
 6# net.ipv4.conf.eth0.rp_filter = 1
 7
 8# Disables IP source routing
 9# Default should work for all interfaces
10net.ipv4.conf.default.accept_source_route = 0
11# net.ipv4.conf.all.accept_source_route = 0
12# net.ipv4.conf.lo.accept_source_route = 0
13# net.ipv4.conf.eth0.accept_source_route = 0
14
15# Controls the System Request debugging functionality of the kernel
16kernel.sysrq = 0
17
18# Controls whether core dumps will append the PID to the core filename.
19# Useful for debugging multi-threaded applications.
20kernel.core_uses_pid = 1
21
22# Increase maximum amount of memory allocated to shm
23# Only uncomment if needed!
24# kernel.shmmax = 67108864
25
26# Disable ICMP Redirect Acceptance
27# Default should work for all interfaces
28net.ipv4.conf.default.accept_redirects = 0
29# net.ipv4.conf.all.accept_redirects = 0
30# net.ipv4.conf.lo.accept_redirects = 0
31# net.ipv4.conf.eth0.accept_redirects = 0
32
33# enable Log Spoofed Packets, Source Routed Packets, Redirect Packets
34# Default should work for all interfaces
35net.ipv4.conf.default.log_martians = 1
36# net.ipv4.conf.all.log_martians = 1
37# net.ipv4.conf.lo.log_martians = 1
38# net.ipv4.conf.eth0.log_martians = 1
39
40# Decrease the time default value for tcp_fin_timeout connection
41net.ipv4.tcp_fin_timeout = 25
42
43# Decrease the time default value for tcp_keepalive_time connection
44net.ipv4.tcp_keepalive_time = 1200
45
46# Turn on the tcp_window_scaling
47net.ipv4.tcp_window_scaling = 1
48
49# Turn on the tcp_sack
50net.ipv4.tcp_sack = 1
51
52# tcp_fack should be on because of sack
53net.ipv4.tcp_fack = 1
54
55# Turn on the tcp_timestamps
56net.ipv4.tcp_timestamps = 1
57
58# Enable TCP SYN Cookie Protection
59net.ipv4.tcp_syncookies = 1
60
61# Enable ignoring broadcasts request
62net.ipv4.icmp_echo_ignore_broadcasts = 1
63
64# Enable bad error message Protection
65net.ipv4.icmp_ignore_bogus_error_responses = 1
66
67# make more local ports available
68# net.ipv4.ip_local_port_range = 1024 65000
69
70# set TCP Re-Ordering value in kernel to ‘5′
71net.ipv4.tcp_reordering = 5
72
73# Lower syn retry rates
74net.ipv4.tcp_synack_retries = 2
75net.ipv4.tcp_syn_retries = 3
76
77# Set Max SYN Backlog to ‘2048′
78net.ipv4.tcp_max_syn_backlog = 2048
79
80# Various Settings
81net.core.netdev_max_backlog = 1024
82
83# Increase the maximum number of skb-heads to be cached
84net.core.hot_list_length = 256
85
86# Increase the tcp-time-wait buckets pool size
87net.ipv4.tcp_max_tw_buckets = 360000
88
89# This will increase the amount of memory available for socket input/output queues
90net.core.rmem_default = 65535
91net.core.rmem_max = 8388608
92net.ipv4.tcp_rmem = 4096 87380 8388608
93net.core.wmem_default = 65535
94net.core.wmem_max = 8388608
95net.ipv4.tcp_wmem = 4096 65535 8388608
96net.ipv4.tcp_mem = 8388608 8388608 8388608
97net.core.optmem_max = 40960

1# Disable ping requests
2net.ipv4.icmp_echo_ignore_all = 1

1/sbin/sysctl -p
2/sbin/sysctl -w net.ipv4.route.flush=1