not able to find ifcfg-enp0s3 in /etc/sysconfig/network-scripts? - linux

i want to change the IP Address of my centos7 vm which i have created in virtual box. im able to see the nic cards if i do "ifcfg". but when i go to the path /etc/sysconfig/network-scripts the nic cards are not available. can anyone help me how to change the ip in centos7. i even tried with command "setup"

Create ifcfg-enp0s3 and ifcfg-enp0s8 files manually. The samples are /usr/share/doc/initscripts-*/examples/networking/. However if you use static IP address, essential items are here:
TYPE=Ethernet
BOOTPROTO=none
NAME=enp0s3
DEVICE=enp0s3
ONBOOT=yes
IPADDR=192.168.100.3
NETMASK=255.255.255.0
Or if you prefer to use DHCP :
TYPE=Ethernet
BOOTPROTO=dhcp
NAME=enp0s3
DEVICE=enp0s3
ONBOOT=yes

Related

How do i staticly assign a ip in CentOS7

Trying to follow the guides online but i have no ifcfg-Eth0 or ensp3? or what ever all i have i ifcfg-lo and the contents look nothing like https://www.youtube.com/watch?v=5Hwv6OcfazI https://i.imgur.com/bxovaJ1.png also been trying to assign ip in Ubuntu 18.04 which doesn't use ect/network/interface no more it uses Netplan and even after i edit that and apply it i never have internet access. why on earth is linux so difficult to give addresses, i also tried the GUI way but i can never get online after. Is it something to do with Vmware?
You must add nic to your VM and centos must have driver for this nic. After that you can ask a question in "Unix & Linux Stack Exchange" (how to configure network connection in centos7) or try to configure it youself.
I recommend to do something like:
[root#centos7]# nmcli con show
NAME UUID TYPE DEVICE
enp0s3 d77bd8ad-ec13-4442-bb2b-ccee7a697552 ethernet enp0s3
[root#centos7minimal network-scripts]# nmcli con mod "enp0s3" ipv4.address "192.168.1.2/25, 192.168.1.3/32" ipv4.gateway "192.168.1.1" ipv4.dns "192.168.1.1, 8.8.8.8"
[root#centos7minimal network-scripts]# nmcli con up enp0s3
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/2)

Virtual machine- setup centos as router

Here is my situation,
i need to configure linux system as router and client are also in virtual machine..
System A
eth0: takes ip from isp(Configured as Bidge in VM ware)
eth1:
DEVICE=eth1
BOOTPROTO=static
ONBOOT=yes
HWADDR=00:0c:29:0a:eb:ec
IPADDR=192.168.100.1
NETMASK=255.255.255.0
IPV6INIT=no
TYPE=Ethernet
PREFIX=24
GATEWAY=192.168.100.1
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
Controls IP packet forwarding
net.ipv4.ip_forward = 1
route add -net 192.168.100.0 netmask 255.255.255.0 gw 192.168.100.1 dev eth1
This is so far what i have done in system A....
and in System B
I have configured static IP address
DEVICE=eth0
BOOTPROTO=static
ONBOOT=yes
HWADDR=00:0c:29:0a:eb:ec
IPADDR=192.168.100.2
NETMASK=255.255.255.0
GATEWAY=192.168.100.1
Both System A and System B are Virtual OS. SystemA is considered as router and System B is considered as client...
AM i missing something...
Thanks in Advance
Adding the route is wrong. That route will be added automatically as it's an interface connected route.
What you probably did wrong is not configuring a DNS server.
If you provide more details we can give a better answer.

DNSclient is not picking up hostname from DNSserver but it is able to ping it

I Have Window 7 as Host Machine and I have installed Redhat 5.3 and Centos 5.4 as Vmware Machines under Window 7 through Vmware Workestation.I configure DNS & DHCP in Redhat 5.3(10.0.0.1) and able to do nslookup & DIG in this.I am able to ping window 7,redhat,centos with each other.
I have made one entry client30.example.com for ip 10.0.0.30 in forword and backword lookup file in DNS server(10.0.0.1).
Problem :-
Centos whom i have made dhcp client of Redhat(10.0.0.1) is able to get ip from dhcp server and it gets ip 10.0.0.30 (as i wanted no problem till now)
But Centos is not picking up hostanme client30.example.com as i have bind entry of ip 10.0.0.30 with client30.example.com.
Still it is picking up hostname localhost.localdomain. I check /etc/resolve.conf file of centos and i found that by default it picks nameserver 192.168.1.1(even i have not provided this ip anywhere).Everytime i made manual change in this ip again it pics same ip on reboot.
Kindly help how i can resolve this problem.
Because VMware Workstation is itself DHCP. Please disable DHCP in VMware Workstation, You can't run two DHCP in single network subnet.
Also check /etc/sysconfig/network file, Hostname coming from there.

Xen configure host-only adapter

Xen hypervisor has 2 modes for network configuration as I've seen in Virtual Manager. 1 NAT 2 Routed. Both ask for IP Subnet. However i want to configure a network where i could assign any IP instead of being assigned by DHCP of Xen.
I've use oracle Virtual Box there is an option to use Host-only adapter. I want to use Xen in that way.
In other words i want to share physical network interface to guest machine(VM)
I'm using Xen Hypervisor 3.x on CentOS 6.2 x86_64
I did the following to solve the issue this worked for me.
Disabling Xen's network scripts
If using Xen it is recommended to disable its network munging by editing /etc/xen/xend-config.sxp and changing the line
(network-script network-bridge)
To be
(network-script /bin/true)
Disabling NetworkManager
As of the time of writing (Fedora 12), NetworkManager still does not support bridging, so it is necessary to use "classic" network initscripts for the bridge, and to explicitly mark them as independent from NetworkManager (the "NM_CONTROLLED=no" lines in the scripts below).
If desired, you can also completely disable the NetworkManager:
# chkconfig NetworkManager off
# chkconfig network on
# service NetworkManager stop
# service network start
Creating network initscripts
In the /etc/sysconfig/network-scripts directory it is neccessary to create 2 config files. The first (ifcfg-eth0) defines your physical network interface, and says that it will be part of a bridge:
# cat > ifcfg-eth0 <<EOF
DEVICE=eth0
HWADDR=00:16:76:D6:C9:45
ONBOOT=yes
BRIDGE=br0
NM_CONTROLLED=no
EOF
Obviously change the HWADDR to match your actual NIC's address. You may also wish to configure the device's MTU here using e.g. MTU=9000.
The second config file (ifcfg-br0) defines the bridge device:
# cat > ifcfg-br0 <<EOF
DEVICE=br0
TYPE=Bridge
BOOTPROTO=dhcp
ONBOOT=yes
DELAY=0
NM_CONTROLLED=no
EOF
WARNING: The line TYPE=Bridge is case-sensitive - it must have uppercase 'B' and lower case 'ridge'
After changing this restart networking (or simply reboot)
# service network restart
Visit for more details
For Xen, this is just a special case of bridged networking.
You create a dummy bridge on your CentOS Dom0, then connect your VM to that bridge.
From the CentOS Documention (http://www.centos.org/docs/5/html/5.2/Virtualization/sect-Virtualization-Virtualized_network_devices-Laptop_network_configuration.html)
create a dummy0 network interface and assign it a static IP address.
In our example I selected 10.1.1.1 to avoid routing problems in our environment. To enable dummy device support add the following lines to /etc/modprobe.conf
alias dummy0 dummy
options dummy numdummies=1
To configure networking for dummy0 edit/create /etc/sysconfig/network-scripts/ifcfg-dummy0:
DEVICE=dummy0
BOOTPROTO=none
ONBOOT=yes
USERCTL=no
IPV6INIT=no
PEERDNS=yes
TYPE=Ethernet
NETMASK=255.255.255.0
IPADDR=10.1.1.1
ARP=yes
You can then just connect your VM to the dummy0 bridge device
Additional Reference
http://wiki.xen.org/wiki/HostConfiguration/Networking

It can't be throw over gateway using bonding on CentOS 6

I'll try to bonding(NIC RAID) on CentOS6.
(It can meet preconditions to connect the Internet with eachother NICs.)
I set some parameters in some files, which are "/etc/modprobe.d/bonding.conf",
"/etc/sysconfig/network-scripts/ifcfg-bond0","/etc/sysconfig/network-scripts/ifcfg-eth0",
"/etc/sysconfig/network-scripts/ifcfg-eth1", ..., and "/etc/sysconfig/network-scripts/ifcfg-eth3".
In "/etc/modprobe.d/bonding.conf" is
alias bond0 bonding
options bonding mode=1 miimon=200 primary=eth0
In "/etc/sysconfig/network-scripts/ifcfg-bond0" is
DEVICE=bond0
IPADDR=192.168.1.xxx
NETMASK=255.255.255.0
NETWORK=192.168.1.0
BROADCAST=192.168.1.255
DNS1=xxx.xxx.xxx.1
ONBOOT=yes
TYPE=Ethernet
BOOTPROTO=static
USERCTL=no
PEERDNS=no
In "/etc/sysconfig/network-scripts/ifcfg-eth1" is
DEVICE=eth0
ONBOOT=yes
TYPE=Ethernet
MASTER=bond0
SLAVE=yes
BOOTPROTO=static
HADDR=xx:xx:xx:xx
DNS1=xxx.xxx.xxx.1
I set same parameters "/.../ifcfg-eth1", "/.../ifcfg-eth2" and "/.../ifcfg-eth3" except of "DEVICE"and HADDR.
After I restert network devices with "service network restart".
then show in display "Devide not Managed by NetworkManager". so I did reboot the machine.
As I check them with some operations.
I input "ifconfig -a", the result is normal.
I input "ping xxx.xxx.1.1(Gateway server IP Address), the result is
normal.
I input "ping 216.239.27.104(the IP Address is Google's server)",
the result is Error.(DNS wasn't system down then)
I input "ping google.com", the result is Error.
I input "dig", the result is normal(DNS server's IP Address was
showed)
I seem this problem coase by Gateway's IP Address, But I don't know the way how to.
And my solution is speculation.
Please tell me how to do for resolve this problem.
It sounds like you have a server where the GUI is installed. I believe NetworkManager is hijacking.
yum list | grep -i networkmanager
See if it's installed, you can try stopping the process or removing it if not using GUI. Have had similar issue.

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