1.vi /etc/sysctl.conf
net.ipv4.conf.lo.arp_ignore = 1
net.ipv4.conf.lo.arp_announce = 2
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
2.vi /etc/security/limits.conf
* soft nofile 262144
* hard nofile 262144
3./etc/security/下一看。centos6多出来一个limits.d目录，下面有个文件： 90-nproc.config
* soft nproc 1024
这里限制了1024呀，果断注释。