Explore information related to networking


Enable private networking Vultr - Step by Step Process ?


This article covers how to enable private networking vultr for our customers. Vultr provides many flexible networking options for your cloud servers. Private networks do not have DHCP. When deploying a Vultr cloud server with private networking, you must manually configure the private adapters or supply your own DHCP server. 


To setup a private IP address:

  • Allocate an IP range.
  • Go to the VPC networks page in the Cloud Console. Open the VPC networks page.
  • Under Name, click the VPC network in which you want to create a private Cloud Data Fusion instance.
  • On the VPC network details page, click the Private service connection tab.
  • Click Allocate IP range.

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Create Private Network Bridge on Proxmox VE 6 with NAT


This article covers how to create a Private Network Bridge on Proxmox. 

To do this:

1. Enable paket forwarding in /etc/sysctl.conf on the Proxmox host

2. Edit /etc/network/interfaces on the ProxMox host, to get 10.10.10.0/24 for your containers, that route through eth0 of the ProxMox host

Code:
# network interface settings; autogenerated# Please do NOT modify this file directly, unless you know what
# you're doing.
#
# If you want to manage parts of the network configuration manually,
# please utilize the 'source' or 'source-directory' directives to do
# so.
# PVE will preserve these directives, but will NOT read its network
# configuration from sourced files, so do not attempt to move any of
# the PVE managed interfaces into external files!
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet static
address YOUR-PUBLIC-STATIC-IP/YOUR-PUBLIC-MASK
gateway YOUR-STATIC-GATEWAY
auto vmbr1
iface vmbr1 inet static
address 10.10.10.1
netmask 255.255.255.0
bridge_ports none
bridge_stp off
bridge_fd 0
post-up iptables -t nat -A POSTROUTING -s '10.10.10.0/24' -o eth0 -j MASQUERADE
post-down iptables -t nat -D POSTROUTING -s '10.10.10.0/24' -o eth0 -j MASQUERADE


3. Configure a container inside 10.10.10.0/24 - as an example using 10.10.10.2 .

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Guest unable to reach host using macvtap interface - Fix it Now


This article covers how to fix the issue with guests unable to reach the host using macvtap interface.

This issue happens when A guest virtual machine can communicate with other guests, but cannot connect to the host machine after being configured to use a macvtap (also known as type='direct') network interface.


To resolve this error (guests unable to reach the host using macvtap interface), simply create an isolated network with libvirt:

1. Add and save the following XML in the /tmp/isolated.xml file. If the 192.168.254.0/24 network is already in use elsewhere on your network, you can choose a different network.

<network>

  <name>isolated</name>

  <ip address='192.168.254.1' netmask='255.255.255.0'>

    <dhcp>

      <range start='192.168.254.2' end='192.168.254.254' />

    </dhcp>

  </ip>

</network>

2. Create the network with this command: virsh net-define /tmp/isolated.xml

3. Set the network to autostart with the virsh net-autostart isolated command.

4. Start the network with the virsh net-start isolated command.

5. Using virsh edit name_of_guest, edit the configuration of each guest that uses macvtap for its network connection and add a new <interface> in the <devices> section similar to the following (note the <model type='virtio'/> line is optional to include):

<interface type='network'>

  <source network='isolated'/>

  <model type='virtio'/>

</interface>

6. Shut down, then restart each of these guests.

Since this new network is isolated to only the host and guests, all other communication from the guests will use the macvtap interface.

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Create CentOS Fedora RHEL VM Template on KVM - How to do it


This article covers how to create CentOS/Fedora/RHEL VM Templates on KVM. VM Templates are more useful when deploying high numbers of similar VMs that require consistency across deployments. If something goes wrong in an instance created from the Template, you can clone a fresh VM from the template with minimal effort.


To install KVM in your Linux system:

The KVM service (libvirtd) should be running and enabled to start at boot.

$ sudo systemctl start libvirtd

$ sudo systemctl enable libvirtd

Enable vhost-net kernel module on Ubuntu/Debian.

$ sudo modprobe vhost_net

# echo vhost_net | sudo tee -a /etc/modules


How to Prepare CentOS / Fedora / RHEL VM template ?

1. Update system

After you finish VM installation, login to the instance and update all system packages to the latest versions.

$ sudo yum -y update

2. Install standard basic packages missing:

$ sudo yum install -y epel-release vim bash-completion wget curl telnet net-tools unzip lvm2 

3. Install acpid and cloud-init packages.

$ sudo yum -y install acpid cloud-init cloud-utils-growpart

$ sudo sudo systemctl enable --now acpid

4. Disable the zeroconf route

$ echo "NOZEROCONF=yes" | sudo tee -a /etc/sysconfig/network

5. Configure GRUB_CMDLINE_LINUX – For Openstack usage.

If you plan on exporting template to Openstack Glance image service, edit the /etc/default/grub file and configure the GRUB_CMDLINE_LINUX option. Your line should look like below – remove rhgb quiet and add console=tty0 console=ttyS0,115200n8.

GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=cl/root rd.lvm.lv=cl/swap console=tty0 console=ttyS0,115200n8"

Generate grub configuration.

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

6. Install other packages you need on your baseline template.

7. When done, power off the virtual machine.


How to Clean VM template ?

You need virt-sysprep tool for cleaning the instance.

$ sudo virt-sysprep -d centos7

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Manage Networking with NetworkManager in RHEL CentOS 8


This article covers NetworkManager daemon for managing the networking service to dynamically configure and control network devices and keep connections up and active when they are available.
Netstat is a command line utility that can be used to list out all the network (socket) connections on a system.
It lists out all the tcp, udp socket connections and the unix socket connections.
To reboot Linux using the command line: To reboot the Linux system from a terminal session, sign in or “su”/”sudo” to the “root” account.
Then type “ sudo reboot ” to reboot the box. Wait for some time and the Linux server will reboot itself.

To troubleshoot network connectivity with Linux server:
i. Check your network configuration.
ii. Check the network configuration file.
iii. Check the servers DNS records.
iv. Test the connection both ways.
v. Find out where the connection fails.
vi. Firewall settings.
vii. Check Host status information.

To change the hostname in Linux Ubuntu:
i. Type the following command to edit /etc/hostname using nano or vi text editor: sudo nano /etc/hostname. Delete the old name and setup new name.
ii. Next Edit the /etc/hosts file: sudo nano /etc/hosts.
iii. Reboot the system to changes take effect: sudo reboot.

To reinstall #network service in #Linux (#Ubuntu / #Debian):
i. Use the following command to restart the server networking service. # sudo /etc/init.d/networking restart or
# sudo /etc/init.d/networking stop # sudo /etc/init.d/networking start else # sudo systemctl restart networking.
ii. Once this done, use the following command to check the server network status.

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Remote Transport Pruning Failure How to troubleshoot


This article will guide you on steps to solve remote transport #pruning #failure in #cPanel which can occur when a directory has too much size, network #error, or due to the lowness of backup drive.

The remote transport process may time out if it tries to prune a very large directory. The following options can help you to solve this issue:

The transport may produce an error if it is unable to prune the directory due to its size. You can manually delete the directory from the remote backup location to troubleshoot this error.

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How to use netsh to configure port forwarding on windows


This article will guide you on how to configure port forwarding on windows using netsh in order to redirect an incoming TCP connection from the local TCP port to any other port number.

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