优化linux系统并防止入侵操作(修改内核参数)

vim /etc/sysctl.conf 来改内核参数。

优化内核参数
net.ipv4.tcp_fin_timeout = 2

net.ipv4.tcp_tw_reuse = 1

net.ipv4.tcp_tw_recycle = 1

net.ipv4.tcp_syncookies = 1

net.ipv4.tcp_keepalive_time =600

net.ipv4.ip_local_port_range = 4000    65000

net.ipv4.tcp_max_syn_backlog = 16384

net.ipv4.tcp_max_tw_buckets = 36000

net.ipv4.route.gc_timeout = 100

net.ipv4.tcp_syn_retries = 1

net.ipv4.tcp_synack_retries = 1

net.core.somaxconn = 16384

net.core.netdev_max_backlog = 16384

net.ipv4.tcp_max_orphans = 16384

 

以下参数是对iptables防火墙的优化,防火墙不开会有提示,可以忽略不理。

net.ipv4.ip_conntrack_max = 25000000

net.ipv4.netfilter.ip_conntrack_max = 25000000

net.ipv4.netfilter.ip_conntrack_tcp_timeout_established = 180

net.ipv4.netfilter.ip_conntrack_tcp_timeout_time_wait = 120

net.ipv4.netfilter.ip_conntrack_tcp_timeout_close_wait = 60

net.ipv4.netfilter.ip_conntrack_tcp_timeout_fin_wait = 120

 

sysctl -p命令可以使改过的内容生效

 

 

隐藏linux系统版本号

>/etc/issue   或   cat /dev/null >/etc/issue

 

锁定关键系统文件

chattr +i /etc/passwd /etc/shadow /etc/group /etc/gshadow /etc/inittab

解锁关键系统文件

chattr -i /etc/passwd /etc/shadow /etc/group /etc/gshadow /etc/inittab

查看内容是否加锁了

lsattr /路径

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