vmlinuz initrd=initrd.img linux dd quiet

vmlinuz initrd=initrd.img inst.stage2=hd:/dev/sdb4 quiet

vi /etc/default/grub

#line6 add

ipv6.disable=

grub2-mkconfig -o /boot/grub2/grub.cfg

reboot

echo "ulimit -SHn 102400" >> /etc/rc.local

cat >> /etc/security/limits.conf << EOF

 *           soft   nofile

 *           hard   nofile

 *           soft   nproc

 *           hard   nproc

EOF

tzselect

yum install -y ntpdate

ntpdate -d time.nist.gov
hwclock -w

vi /etc/sysconfig/network-scripts/ifcfg-enp2s0

ONBOOT=yes

vi /etc/profile

#add last line

export PATH=$PATH:/usr/local/ruby/bin

source /etc/profile

rpm -qa postfix

rpm -e --nodeps postfix