Google is a huge company which provides paid and free services. It mainly operates in IT and internet area. Internet uses DNS in order to solve domain names into IP addresses. Because internet infrastructure works with IP addresses. Google provides free DNS servers which can be used for fast and free domain resolution. In this tutorial we will learn Google DNS features and how to use in Linux, Ubuntu, Debian,...
New comers to the Linux generally asks for what is the purpose and usage of the /etc/hosts file. /etc directory holds system and service related configuration. hosts file is used to store host name or DNS to IP address resolution. It provides easy way to match a host or DNS name with an IP address. List Current Host or DNS to IP Address Resolutions We can easily read and print current content...
Hostname is used to identify the Linux hosts. We generally prefer to put related host names to the systems like web1, db5 etc. In this tutorial we will look how to find and print hostname and change it with different methods. Following examples can be used for other Linux distributions like CentOS, Fedora, RedHat too. Find Current Hostname There are different ways to find hostname. But the most easy and...
Tcpdump is everyday tool used by system and network administrator. We generally look simple use cases like host, port and protocol filter for tcpdump . In this tutorial we will look how to filter host, port and protocol in tcpdump. But keep in mind that tcpdump will requires administrator or root privileges. We can use root account or sudo command in order to gain root privileges. Specify Host Name Tcpdump can resolve host...
Nmap is popular tool used by pentesters, system administrators and network administrators. Nmap provides a lot of features for free. In this tutorial, we will look host discovery features and options of nmap. Discover with Ping Scan One of the basic usages for Host discovery is Ping scan. Ping uses ICMP protocol to communicate with targets. Targets generally responses Ping r ICMP requests which show the remote system is up....
[rps-include post=6632] Performance is important part of the scan. Nmap developers always looks for optimized and adjustable performance options. Adjustable scan performance is important because scanning big networks will require a lot of time to complete job. As a security analyzer or pentester time is important for us. Set Host Group Count Nmap have the ability to scan multiple hosts in parallel. This is done by dividing target to the...
[rps-include post=6632] Requirement for scanning is target specification. Nmap provides different methodologies to set targets. Single Host Address This is the simplest and mostly used target specification. We only provide single ip address.
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$ nmap 192.168.1.1 |
192.168.1.1 is the target ip address Dns Name Nmap can use DNS names as targets. It will resolve DNS addresses into ip addresses. Be sure that DNS is working in the system
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$ nmap localhost.com |
localhost.com is the DNS name...
DHCP is a protocol used to provide network related configuration to the network hosts. Mainly IP address information, network gateway, network mask and DNS server information are provided by DHCP protocol. DHCP have more features like providing boot file over network etc. In this tutorial we will look how DHCP reservation works for Windows Server 2012, Windows Server 2008, Cisco and benefits of using dhcp reservation. More information about DHCP...
Virtualbox is virtualization tool used to create virtual machines. Virtual machines can be cloned, created, deleted without affecting any external source in the host system. In this tutorial we will look how to install Virtualbox virtualization software in Windows operating systems. Download VirtualBox We will download Virtualbox from following link. http://download.virtualbox.org/virtualbox/5.1.18/VirtualBox-5.1.18-114002-Win.exe Virtualbox have different versions for different platforms and operating systems like OS X, Linux, Solaris. User Manual The user...
While trying to ping or connect a remote host I can an error “no route to host”. How can I debug this error and solve it? As we know IP networks are constructed hop by hop which means there are different intermediate routers transmit packets between two remote hosts. These routers decides the route to the destination according to their routing tables. If destination route do not exists in the...
