New CentOS 7 Server Setup Commands

Post install configuration

Update /etc/yum.repo.d/CentOS-Base.repo for archive support

# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client.  You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
#

[base]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os&infra=$infra
#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
baseurl=http://vault.centos.org/7.9.2009/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

#released updates
[updates]
name=CentOS-$releasever - Updates
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates&infra=$infra
#baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/
baseurl=http://vault.centos.org/7.9.2009/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras&infra=$infra
#baseurl=http://mirror.centos.org/centos/$releasever/extras/$basearch/
baseurl=http://vault.centos.org/7.9.2009/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus&infra=$infra
#baseurl=http://mirror.centos.org/centos/$releasever/centosplus/$basearch/
baseurl=http://vault.centos.org/7.9.2009/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

Remove Network Manager software

# /bin/systemctl disable NetworkManager
# /bin/systemctl disable NetworkManager-dispatcher
# yum erase NetworkManager-tui NetworkManager-glib NetworkManager

Configure Network

Run the commands below to set up a static ip address (192.168.1.221) and hostname (test-centos-1).

# export remote_hostname=guest1
# export remote_ip=192.168.1.221
# export remote_gateway=192.168.1.1

# hostnamectl set-hostname $remote_hostname

# sed -i.bak "s/.*BOOTPROTO=.*/BOOTPROTO=none/g" /etc/sysconfig/network-scripts/ifcfg-eth0

# cat << EOF >> /etc/sysconfig/network-scripts/ifcfg-eth0
IPADDR0=$remote_ip
PREFIX0=24
GATEWAY0=$remote_gateway
DNS1="216.136.95.2"
DNS2="64.132.94.250"
NM_CONTROLLED="no"
EOF

# systemctl restart network
# systemctl enable network.service
# systemctl enable sshd
# systemctl start sshd

# echo "checking connectivity"
# ping www.google.com

Disable selinux

# setenforce 0
# sed -i.bak "s/^SELINUX=.*/SELINUX=disabled/g" /etc/selinux/config

Remove Postfix, and add needed packages.

# yum -y erase postfix
# yum -y install finger nc net-snmp net-snmp-perl net-snmp-utils ntp perl-Date-Manip \
    perl-DBD-SQLite sendmail sendmail-cf sssd tcp_wrappers tcpdump telnet tftp \
    tog-pegasus traceroute vim-enhanced wget oddjob-mkhomedir net-tools yum-cron \
     bind-utils

Alternately, you can leave Postfix and just install needed packages.

# yum -y install finger nc net-snmp net-snmp-perl net-snmp-utils ntp perl-Date-Manip \
    perl-DBD-SQLite sssd tcp_wrappers tcpdump telnet tftp tog-pegasus traceroute \
    vim-enhanced wget oddjob-mkhomedir net-tools yum-cron  bind-utils

Fix Time Zone

# rm -f /etc/localtime
# ln -s /usr/share/zoneinfo/MST7MDT /etc/localtime

Turn off rp_filter

# echo "net.ipv4.conf.default.rp_filter = 0" > /etc/sysctl.d/rpfilter.conf

Update required Packages

# yum update kernel bash nss nspr ntp glibc cvs

Reboot Server to apply new kernel

# shutdown -r now

Remove old kernel so system scans cleanly and update kernel tools

# rpm -qa | grep kernel
# yum -y erase kernel-<old kernel version>
# yum -y update kernel-tools kernel-tools-libs

Install VM Tools

If this is a virtual machine, install the open vm tools.

# yum -y install open-vm-tools