---------------------------------------------
Things to do after installation of CentOS-7
---------------------------------------------
-------------------------------------------
1) Install Following Required Commands
-------------------------------------------
yum install net-tools # -----> Install ifconfig Command
yum install wget # -----> Install wget Command
yum install lsof # -----> Install lsof Command
yum install mlocate # -----> Install updatedb Command
yum install bind-utils # -----> Install nslookup Command
yum group install "Development Tools" # -----> Install GCC and Development Tools
yum install mailx # -----> Install mail Command
Command to list groups on a CentOS 7
# yum group list
-------------------------------------------
2) Set Hostname
-------------------------------------------
echo 192.168.1.111 test.deva.com deva >> /etc/hosts
echo test.deva.com > /etc/hostname
-------------------------------------------
3) Set Bashrc Setting
-------------------------------------------
[root@localhost ~]#vi /etc/bashrc
#-------------------------------------------
#Custome CHANGES START
#-------------------------------------------
alias c='clear'
alias df='df -Th'
export HISTSIZE=10000
export HISTTIMEFORMAT="%h %d %H:%M:%S "
export HISTFILESIZE=10000…
#-------------------------------------------
#Custome CHANGES END
#-------------------------------------------
To apply bashrc changes , lgout from server & login again OR
run follwoing command
[root@localhost ~]#. /etc/bashrc
-------------------------------------------
4) Update Kernel
-------------------------------------------
[root@localhost ~]# yum update kernel
---------------------------------------------
5)Enable iptables (instead of firewalld)
---------------------------------------------
### Stop firewalld ###
#systemctl disable firewalld.service
#systemctl stop firewalld.service
### Install IPtables ###
# yum install iptables-services
Re-run the command to restart the iptables:
# service iptables restart
#systemctl enable iptables.service
#systemctl start iptables.service
#systemctl enable ip6tables.service
#systemctl start ip6tables.service
-------------------------------------------
6) Change NIC Name
-------------------------------------------
Change the default network interface name to “eth0′′
CentOS7 has a default nic name as “en016.....”,
# vi /etc/default/grub
Search for the line “GRUB_CMDLINE_LINUX” and append the following: “net.ifnames=0 biosdevname=0′′
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="vconsole.font=latarcyrheb-sun16 vconsole.keymap=us rd.lvm.lv=centos/root crashkernel=auto rhgb quiet"
GRUB_DISABLE_RECOVERY="true"
Then it Will look like this:
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="vconsole.font=latarcyrheb-sun16 vconsole.keymap=us rd.lvm.lv=centos/root crashkernel=auto rhgb quiet net.ifnames=0 biosdevname=0"
GRUB_DISABLE_RECOVERY="true"
We had just added net.ifnames=0 biosdevname=0 in second last line.
Create a new configuration based on the currently running system using grub2-mkconfig command:
# grub2-mkconfig -o /boot/grub2/grub.cfg
Rename the interface files by renaming the file
# mv /etc/sysconfig/network-scripts/ifcfg-eno16777736 /etc/sysconfig/network-scripts/ifcfg-eth0
Reboot the system:
# reboot
After reboot, check the interface name:
# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.100 netmask 255.255.255.0 broadcast 192.168.58.255
inet6 fe80::20c:29ff:fe6e:b0ae prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:6e:b0:ae txqueuelen 1000 (Ethernet)
RX packets 25336 bytes 2829386 (2.6 MiB)
RX errors 0 dropped 11 overruns 0 frame 0
TX packets 172 bytes 35789 (34.9 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
-------------------------------------------
6) Configure the static ip on the server
-------------------------------------------
Edit the interface file under /etc/sysconfig/network-scripts/ directory:
# vi /etc/sysconfig/network-scripts/ifcfg-eth0
Here is my ifcfg-eth0 file as a sample, please change it according to your requirement:
DEVICE="eth0"
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.1.100
NETMASK=255.255.255.0
GATEWAY=192.168.1.1
DNS1=192.168.1.1
Stop and disable the NetworkManager service, because we don’t need it on the server:
# systemctl stop NetworkManager
# systemctl disable NetworkManager
Restart the network service(Be careful, if you are connecting remotely, because you will be disconnected after issue this command):
# service network restart
-------------------------------------------
7) Disable IPv6:(If U dont have use of IPV6)
-------------------------------------------
First check that IPv6 is enabled or not:
[root@localhost ~]# lsmod | grep -i ipv6
nf_conntrack_ipv6 18738 5
nf_defrag_ipv6 34651 1 nf_conntrack_ipv6
nf_nat_ipv6 13279 1 ip6table_nat
nf_nat 21798 4 nf_nat_ipv4,nf_nat_ipv6,ip6table_nat,iptable_nat
nf_conntrack 101024 8 nf_nat,nf_nat_ipv4,nf_nat_ipv6,xt_conntrack,ip6table_nat,iptable_nat,nf_conntrack_ipv4,nf_conntrack_ipv6
Edit the grub file:
# vi /etc/default/grub
Search for the line “GRUB_CMDLINE_LINUX” and add the following at the beginning: “ipv6.disable=1′′ Will look like this:
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="vconsole.font=latarcyrheb-sun16 vconsole.keymap=us rd.lvm.lv=centos/root crashkernel=auto rhgb quiet"
GRUB_DISABLE_RECOVERY="true"
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="ipv6.disable=1 vconsole.font=latarcyrheb-sun16 vconsole.keymap=us rd.lvm.lv=centos/root crashkernel=auto rhgb quiet"
GRUB_DISABLE_RECOVERY="true"
Create a new configuration based on the currently running system using grub2-mkconfig command:
# grub2-mkconfig -o /boot/grub2/grub.cfg
Reboot the system:
# reboot
Once again, check the IPv6 on the system:
lsmod | grep -i ipv6
-------------------
End Of Document
-------------------
Things to do after installation of CentOS-7
---------------------------------------------
-------------------------------------------
1) Install Following Required Commands
-------------------------------------------
yum install net-tools # -----> Install ifconfig Command
yum install wget # -----> Install wget Command
yum install lsof # -----> Install lsof Command
yum install mlocate # -----> Install updatedb Command
yum install bind-utils # -----> Install nslookup Command
yum group install "Development Tools" # -----> Install GCC and Development Tools
yum install mailx # -----> Install mail Command
Command to list groups on a CentOS 7
# yum group list
-------------------------------------------
2) Set Hostname
-------------------------------------------
echo 192.168.1.111 test.deva.com deva >> /etc/hosts
echo test.deva.com > /etc/hostname
-------------------------------------------
3) Set Bashrc Setting
-------------------------------------------
[root@localhost ~]#vi /etc/bashrc
#-------------------------------------------
#Custome CHANGES START
#-------------------------------------------
alias c='clear'
alias df='df -Th'
export HISTSIZE=10000
export HISTTIMEFORMAT="%h %d %H:%M:%S "
export HISTFILESIZE=10000…
#-------------------------------------------
#Custome CHANGES END
#-------------------------------------------
To apply bashrc changes , lgout from server & login again OR
run follwoing command
[root@localhost ~]#. /etc/bashrc
-------------------------------------------
4) Update Kernel
-------------------------------------------
[root@localhost ~]# yum update kernel
---------------------------------------------
5)Enable iptables (instead of firewalld)
---------------------------------------------
### Stop firewalld ###
#systemctl disable firewalld.service
#systemctl stop firewalld.service
### Install IPtables ###
# yum install iptables-services
Re-run the command to restart the iptables:
# service iptables restart
#systemctl enable iptables.service
#systemctl start iptables.service
#systemctl enable ip6tables.service
#systemctl start ip6tables.service
-------------------------------------------
6) Change NIC Name
-------------------------------------------
Change the default network interface name to “eth0′′
CentOS7 has a default nic name as “en016.....”,
# vi /etc/default/grub
Search for the line “GRUB_CMDLINE_LINUX” and append the following: “net.ifnames=0 biosdevname=0′′
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="vconsole.font=latarcyrheb-sun16 vconsole.keymap=us rd.lvm.lv=centos/root crashkernel=auto rhgb quiet"
GRUB_DISABLE_RECOVERY="true"
Then it Will look like this:
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="vconsole.font=latarcyrheb-sun16 vconsole.keymap=us rd.lvm.lv=centos/root crashkernel=auto rhgb quiet net.ifnames=0 biosdevname=0"
GRUB_DISABLE_RECOVERY="true"
We had just added net.ifnames=0 biosdevname=0 in second last line.
Create a new configuration based on the currently running system using grub2-mkconfig command:
# grub2-mkconfig -o /boot/grub2/grub.cfg
Rename the interface files by renaming the file
# mv /etc/sysconfig/network-scripts/ifcfg-eno16777736 /etc/sysconfig/network-scripts/ifcfg-eth0
Reboot the system:
# reboot
After reboot, check the interface name:
# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.100 netmask 255.255.255.0 broadcast 192.168.58.255
inet6 fe80::20c:29ff:fe6e:b0ae prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:6e:b0:ae txqueuelen 1000 (Ethernet)
RX packets 25336 bytes 2829386 (2.6 MiB)
RX errors 0 dropped 11 overruns 0 frame 0
TX packets 172 bytes 35789 (34.9 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
-------------------------------------------
6) Configure the static ip on the server
-------------------------------------------
Edit the interface file under /etc/sysconfig/network-scripts/ directory:
# vi /etc/sysconfig/network-scripts/ifcfg-eth0
Here is my ifcfg-eth0 file as a sample, please change it according to your requirement:
DEVICE="eth0"
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.1.100
NETMASK=255.255.255.0
GATEWAY=192.168.1.1
DNS1=192.168.1.1
Stop and disable the NetworkManager service, because we don’t need it on the server:
# systemctl stop NetworkManager
# systemctl disable NetworkManager
Restart the network service(Be careful, if you are connecting remotely, because you will be disconnected after issue this command):
# service network restart
-------------------------------------------
7) Disable IPv6:(If U dont have use of IPV6)
-------------------------------------------
First check that IPv6 is enabled or not:
[root@localhost ~]# lsmod | grep -i ipv6
nf_conntrack_ipv6 18738 5
nf_defrag_ipv6 34651 1 nf_conntrack_ipv6
nf_nat_ipv6 13279 1 ip6table_nat
nf_nat 21798 4 nf_nat_ipv4,nf_nat_ipv6,ip6table_nat,iptable_nat
nf_conntrack 101024 8 nf_nat,nf_nat_ipv4,nf_nat_ipv6,xt_conntrack,ip6table_nat,iptable_nat,nf_conntrack_ipv4,nf_conntrack_ipv6
Edit the grub file:
# vi /etc/default/grub
Search for the line “GRUB_CMDLINE_LINUX” and add the following at the beginning: “ipv6.disable=1′′ Will look like this:
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="vconsole.font=latarcyrheb-sun16 vconsole.keymap=us rd.lvm.lv=centos/root crashkernel=auto rhgb quiet"
GRUB_DISABLE_RECOVERY="true"
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="ipv6.disable=1 vconsole.font=latarcyrheb-sun16 vconsole.keymap=us rd.lvm.lv=centos/root crashkernel=auto rhgb quiet"
GRUB_DISABLE_RECOVERY="true"
Create a new configuration based on the currently running system using grub2-mkconfig command:
# grub2-mkconfig -o /boot/grub2/grub.cfg
Reboot the system:
# reboot
Once again, check the IPv6 on the system:
lsmod | grep -i ipv6
-------------------
End Of Document
-------------------
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