CentOS 7 內核優化

 

[root@DaMoWang ~]# vim /etc/sysctl.conf 
#關閉ipv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1

# 避免放大攻擊
net.ipv4.icmp_echo_ignore_broadcasts = 1

# 開啓惡意icmp錯誤消息保護
net.ipv4.icmp_ignore_bogus_error_responses = 1

#關閉路由轉發
net.ipv4.ip_forward = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0

#開啓反向路徑過濾
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1

#處理無源路由的包
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.default.accept_source_route = 0

#關閉sysrq功能
kernel.sysrq = 0

#core文件名中添加pid做爲擴展名
kernel.core_uses_pid = 1

# 開啓SYN洪水攻擊保護
net.ipv4.tcp_syncookies = 1

#修改消息隊列長度
kernel.msgmnb = 65536
kernel.msgmax = 65536

#設置最大內存共享段大小bytes
kernel.shmmax = 68719476736
kernel.shmall = 4294967296

#timewait的數量，默認180000
net.ipv4.tcp_max_tw_buckets = 6000
net.ipv4.tcp_sack = 1
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_rmem = 4096        87380   4194304
net.ipv4.tcp_wmem = 4096        16384   4194304
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216

#每一個網絡接口接收數據包的速率比內核處理這些包的速率快時，容許送到隊列的數據包的最大數目
net.core.netdev_max_backlog = 262144

#限制僅僅是爲了防止簡單的DoS 攻擊
net.ipv4.tcp_max_orphans = 3276800

#未收到客戶端確認信息的鏈接請求的最大值
net.ipv4.tcp_max_syn_backlog = 262144
net.ipv4.tcp_timestamps = 0

#內核放棄創建鏈接以前發送SYNACK 包的數量
net.ipv4.tcp_synack_retries = 1

#內核放棄創建鏈接以前發送SYN 包的數量
net.ipv4.tcp_syn_retries = 1

#啓用timewait 快速回收
net.ipv4.tcp_tw_recycle = 1

#開啓重用。容許將TIME-WAIT sockets 從新用於新的TCP 鏈接
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_fin_timeout = 1

#當keepalive 起用的時候，TCP 發送keepalive 消息的頻度。缺省是2 小時
net.ipv4.tcp_keepalive_time = 30

#容許系統打開的端口範圍
net.ipv4.ip_local_port_range = 1024    65000

#修改防火牆表大小，默認65536
#net.netfilter.nf_conntrack_max=655350
#net.netfilter.nf_conntrack_tcp_timeout_established=1200

# 確保無人能修改路由表
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.default.accept_redirects = 0
net.ipv4.conf.all.secure_redirects = 0
net.ipv4.conf.default.secure_redirects = 0

使其生效

[root@DaMoWang ~]# sysctl -p
sysctl: /etc/sysctl.conf(11): invalid syntax, continuing...
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv4.icmp_echo_ignore_broadcasts = 1
net.ipv4.icmp_ignore_bogus_error_responses = 1
net.ipv4.ip_forward = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
net.ipv4.tcp_syncookies = 1
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
net.ipv4.tcp_max_tw_buckets = 6000
net.ipv4.tcp_sack = 1
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_rmem = 4096        87380   4194304
net.ipv4.tcp_wmem = 4096        16384   4194304
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.core.netdev_max_backlog = 262144
net.ipv4.tcp_max_orphans = 3276800
net.ipv4.tcp_max_syn_backlog = 262144
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_synack_retries = 1
net.ipv4.tcp_syn_retries = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_fin_timeout = 1
net.ipv4.tcp_keepalive_time = 30
net.ipv4.ip_local_port_range = 1024    65000
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.default.accept_redirects = 0
net.ipv4.conf.all.secure_redirects = 0
net.ipv4.conf.default.secure_redirects = 0