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How to determine Linux guest VM virtualization technology

I have a cloud-based virtual machine running Ubuntu and CentOS Linux server. It may or may not be virtualized. How do I determine what kind of virtualization technology (VMWARE/ KVM/ XEN/ VirtualBox/ Container/ lxc/Hyper-V etc.) a Linux guest system running on? How do I find out the virtualization type of a CentOS 7 Linux VPS?
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Sysadmin because even developers need heroes!!!

Linux Iptables Delete postrouting Rule Command

I am a new Linux server sysadmin. I need to delete POSTROUTING rule. How do I delete postrouting rule on Linux server?
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KVM libvirt assign static guest IP addresses using DHCP on the virtual machine

I am using KVM/libvirt on Linux operating system and how do I assign static IP address using dnsmasq dhcpd server for my default virtual network switch?
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How to copy permissions from one file to another on Linux

I need to copy or clone file ownership and permissions from another file on Linux. Is there a bash command line option to clone the user, group ownership and permissions on a file from another file on Linux operating system?
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A stack-based critical buffer overflow was found in the way the libresolv library (glibc) performed dual A/AAAA DNS queries. A remote attacker could crash or, potentially, execute code running the library on Linux. How do I patch and protect my server or workstation against the glibc getaddrinfo on Linux operating system?
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Linux Check Disk Space Command

I recently switched from a Windows server to a Linux server operating system. I am using Ubuntu LTS server. How do I find out disk space utilization information using command line option?
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How To Patch and Protect Linux Kernel Zero Day Vulnerability CVE-2016-0728 [ 19/Jan/2016 ]

A very serious security problem has been found in the Linux kernel. A 0-day local privilege escalation vulnerability has existed since 2012. This bug affects millions of Android or Linux applications to escalate privileges. Any server or desktop (32 or 64 bit) with Linux Kernel version 3.8+ is vulnerable. How do I fix this problem?
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The OpenSSH project released an ssh client bug info that can leak private keys to malicious servers. A man-in-the-middle kind of attack identified and fixed in OpenSSH are dubbed CVE-2016-0777 and CVE-2016-0778. How do I fix OpenSSH’s client vulnerability on a Linux or Unix-like operating system?
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How to list all iptables rules with line numbers on Linux

I recently added NAT rules on my RHEL 6.x system. How do I see the rules including line numbers that I just added in Linux?
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How to check boot path (partition) in Linux

How do I identify the boot device or boot path in Linux operating system?
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