The nslookup (Name Server Lookup) – is a command-line tool for querying DNS (Domain Name System) servers, that is usually can be found on Windows, Linux and macOS systems out of the box. This tool is used for resolving domain names, IP addresses and other specific DNS records. By default, the nslookup command is using […]
dns
IP2Host: Get Hostname from IP – Command Line
A reverse name resolution zone file is used to translate an IP address in a particular namespace into a fully qualified domain name (FQDN). If this file has been configured on a name server, it becomes possible to find a hostname from an IP address. This note shows how to get a hostname from an […]
DNS TTL Lookup – Check Domain TTL (Time To Live) – Dig Command
All DNS records have a TTL (time to live) property that specifies the maximum amount of time the record may be cached. In Linux you can make the DNS TTL lookup using the dig command. You can both check the current domain remaining TTL as well as find out what TTL value is set on […]
Encrypt DNS Traffic With DNSCrypt
This tutorial describes how to install and set up DNSCrypt on Debian based systems, like Linux Mint, Ubuntu etc. DNSCrypt Proxy – is a tool for securing communications between a client and a DNS resolver. It encrypts DNS requests using the DNSCrypt Protocol and pass them to an upstream server, by default OpenDNS. Resolving dependencies […]
Setting Up DNS Records — [CNAME] Record (canonical name record)
What is a [CNAME] Record? A [CNAME] Record or a Canonical Name Record, specifies that the domain name or subdomain is an alias of another, canonical domain name. The value of a CNAME record is always a domain name. What does the [CNAME] Record serve for? [CNAME] Records are useful because they allow you to […]
Setting Up DNS Records — [A] Record (address record)
What is an [A] Record? An [A] Record or an Address Record, assigns an IP address to a domain or subdomain name. The value of an A record is always an IP address. How to check an [A] Record? Use the dig command, to check which IP address is assigned to the domain name. $ […]
Setup DNS Resolution With “resolv.conf” in Examples
The /etc/resolv.conf configuration file contains information that allows a computer to convert alpha-numeric domain names into the numeric IP addresses. The process of converting domain names to IP addresses is called resolving. When using DHCP, dhclient usually rewrites resolv.conf with information received from the DHCP server. How do I edit the “/etc/resolv.conf” file? Use text […]
Setting Up Reverse DNS — PTR Record
What is the reverse DNS? Reverse DNS is an IP address to domain name mapping – the opposite of Forward DNS which maps domain names to IP addresses. Comparison: ## FORWARD LOOKUP ## # host centos.org centos.org has address 72.232.194.162 ## REVERSE LOOKUP ## # host 72.232.194.162 162.194.232.72.in-addr.arpa domain name pointer www.centos.org. What does the […]
HowTo: Get a List of All Sub-Domains of a Domain Name
If you need to find out all the sub-domains of a given domain name, you can try AXFR request. This hint works only if the NS that you are querying is configured to allow AXFR requests. Not all name servers allow AXFR protocol queries. Most of them return “Transfer failed”. The first thing that you […]
Free Fast Public DNS Servers
There are several reasons why you may want to use alternative DNS servers: Speed up your web browsing; Improving your security; Backup solution when your ISP servers are down. Here is a list of Free public DNS servers. Google Public DNS Google Public DNS – Free DNS server list. # For IPv4: nameserver 8.8.8.8 nameserver […]