centos linux tcp最大连接数超出1024 限制修改

centos有一个问题，例如有很多的tcp连接同时连接超出1024个连接数的时候，centos7 会出现一旦到1024则无法连接的情况，

即便你使用limit -n 1024 等这样的修改是无法其效果的，

以及各种修改可能都不起作用：

经过我们的大量研究最终解决了该问题

修改文件 vi /etc/sysctl.conf

如下：

vm.swappiness = 10

net.ipv4.tcp_syncookies = 1

net.ipv4.tcp_tw_reuse = 1

net.ipv4.tcp_tw_recycle = 1

net.ipv4.tcp_fin_timeout = 30

net.ipv4.tcp_keepalive_time = 1200

net.ipv4.ip_local_port_range = 1024 65000

net.ipv4.tcp_max_tw_buckets = 5000

net.ipv4.tcp_mem = 786432 1048576 1572864

net.core.wmem_max = 873200

net.core.rmem_max = 873200

net.ipv4.tcp_wmem = 8192 436600 873200

net.ipv4.tcp_rmem = 32768 436600 873200

net.core.somaxconn = 256

net.core.netdev_max_backlog = 1000

net.ipv4.tcp_max_syn_backlog = 2048

net.ipv4.tcp_retries2 = 5

net.ipv4.tcp_keepalive_intvl = 30

net.ipv4.tcp_keepalive_probes = 3

net.ipv4.conf.lo.arp_ignore = 0

net.ipv4.conf.lo.arp_announce = 0

net.ipv4.conf.all.arp_ignore = 0

net.ipv4.conf.all.arp_announce = 0

net.ipv4.neigh.default.gc_thresh1 = 10240

net.ipv4.neigh.default.gc_thresh2 = 40960

net.ipv4.neigh.default.gc_thresh3 = 81920

fs.file-max = 655360

vm.max_map_count = 262144