Aug 312012

A name server is a server that hosts a network service for providing responses to queries against a directory service. It maps a human-recognizable identifier to a system-internal, identification or addressing component, the program BIND is the most famous name server available on Linux, it can be used to do everything you need from a name server, but sometimes you need less.

Maybe you have a VPS and you want just to manage your DNS name, for this use you could check NSD a great alternative to BIND, it does not do DNS forwarding, it only serves its own domains. but this could be enough for your project.

NSD uses BIND-style zone-files; zone-files used under BIND (named) can usually be supplied unmodified in NSD once declared in the nsd.conf configuration. NSD manages zone information compiled via ‘zonec’ into a binary database file (nsd.db) which allows lightning fast start up of the NSD name-service daemon, syntax structural verification and flagging of errors at database compile-time. All this before being made available to NSD service itself.

Let’s see how to install and configure it.

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Aug 182012

In the past I’ve published articles on how to do a benchmark with namebench to see what’s the fastest DNS server for you and how to crypt your DNS traffic if you use Opendns but I’ve never done a comprehensive guide of the command dig, probably the best command you can have on the command line to query a DNS server, so today I want to show you the basic usage of this command and some trick, using examples that you can re-use for your goals.

But as first thing, probably every reader know what’s a DNS server, but anyway it’s better to take the good definition from Wikipedia:

The Domain Name System (DNS) is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. A Domain Name Service resolves queries for these names into IP addresses for the purpose of locating computer services and devices worldwide.

So let’s see how we can query a DNS server o get all the info we need.

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Sep 252010

networkAfter ping, telnet and dig we continue to see other useful tools for network analysis done by the command line.


traceroute is a computer network tool used to show the route taken by packets across an Internet Protocol (IP) network. An IPv6 variant, traceroute6, is also widely available.

The traceroute tool is available on practically all Unix-like operating systems. Variants with similar functionality are also available, such as tracepath on modern Linux installations and tracert on Microsoft Windows operating systems. Windows NT-based operating systems also provide PathPing, which provides similar functionality.

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CLI tools for Network analysis 1

In two previous articles we saw two instruments that have as output of our analysis a graphic form (ntop and wireshark), but today we will see some tools you can use from the command line: Ping, telnet, dig, traceroute, whois, netstat, nmap, and mtr PING Ping is a computer network administration utility used to test [...]