Category: networking

Link: 10 examples of Linux ss command to monitor network connections

In a previous tutorial we saw how to use the netstat command to get statistics on network/socket connections. However the netstat command has long been deprecated and replaced by the ss command from the iproute suite of tools.

The ss command is capable of showing more information than the netstat and is faster. The netstat command reads various /proc files to gather information. However this approach falls weak when there are lots of connections to display. This makes it slower.

The ss command gets its information directly from kernel space. The options used with the ss commands are very similar to netstat making it an easy replacement.

So in this tutorial we are going to see few examples of how to use the ss command to check the network connections and socket statistics.

Full article here:
10 examples of Linux ss command to monitor network connections (BinaryTides)

Link: How to Do IP Address Geolocation Lookups on Linux

You have probably noticed different services on the Internet which automatically know roughly where you are in the world. From music and video stream services to online stores, these services use a technique, called IP geolocation, which matches your approximate physical location with the IP address you are using. Whenever you connect to the Internet, your device is assigned an IP address from a pool of addresses which are allocated to the different telecommunication companies. The way these addresses work can be quite complicated, but because they are assigned in blocks, it is possible to build a database which maps a block of addresses to a country or even a particular area or city.

The good news is that doing these geolocation lookups isn’t only for the big corporate and mega websites. There are a number of free online services and even a command line tool for Linux which allows you to lookup IP addresses and get information about where that address is assigned. This can be very useful when you are investigating a suspicious email or strange comments left on a blog. It is also useful when using services that mask your IP address, like a VPN, to ensure that they are working as advertised.

Full article here:
How to Do IP Address Geolocation Lookups on Linux (Make Tech Easier)

Links: The DIY home VPN experiment series

Part One: Introduction

It’s been a while since my last blog entry, and I’ve decided to catch you up on some of the projects that I’ve been working on in my home lab. This next series of posts is going to revolve around the do-it-yourself home VPN.

What is a VPN, or virtual private network?

“A VPN is a communications environment in which access is controlled to permit peer connections only within a defined community of interest, and is constructed though some form of partitioning of a common underlying communications medium, where this underlying communications medium provides services to the network on a nonexclusive basis [1].”

In essence, a VPN is private and controlled network communication over a non-private medium – the Internet.

Full articles here (source: empiric virtualization):
Introduction.
Generating a PKI (Public Key Infrastructure) for my OpenVPN.
My Virtualized OpenVPN Server.
Deploying OpenVPN using CentOS on a Raspberry Pi.

Link: How To Install & Configure BIND9 on Raspbian Wheezy

About BIND9

BIND is the most widely used DNS system on the internet, on Unix like operating systems its the de facto standard. Originally written by four graduate students at the Computer Systems Research Group at the University of California, Berkeley (UCB), the name originates as an acronym from Berkeley Internet Name Domain, reflecting the application’s use within UCB. BIND 9 was released in September 2000.

Raspbian is an unofficial port of Debian wheezy armhf with compilation settings adjusted to produce code that uses “hardware floating point”, the “hard float” ABI and will run on the Raspberry Pi.

Full article here:
How To Install & Configure BIND9 on Raspbian Wheezy (Sam Culley)

Link: 18 commands to monitor network bandwidth on Linux server

This post mentions some linux command line tools that can be used to monitor the network usage. These tools monitor the traffic flowing through network interfaces and measure the speed at which data is currently being transferred. Incoming and outgoing traffic is shown separately.

Some of the commands, show the bandwidth used by individual processes. This makes it easy to detect a process that is overusing network bandwidth.

The tools have different mechanisms of generating the traffic report. Some of the tools like nload read the “/proc/net/dev” file to get traffic stats, whereas some tools use the pcap library to capture all packets and then calculate the total size to estimate the traffic load.

Full article here:
18 commands to monitor network bandwidth on Linux server (BinaryTides)

Link: Remotely copy files to and from your Raspberry Pi

Most of the time I remotely log into my Raspberry Pi. Depending on what I am doing I will either SSH into it or VNC into it, which allows me to do almost whatever I would like to.

I say almost as there is a caveat.

What happens when I want to transfer a file to or from the Raspberry Pi?

I have to find a memory stick, plug it into my computer, copy the files onto it, unplug it, plug it into my Raspberry Pi, go back to my computer, copy the files over…

Then if I happen to modify a file and want to transfer it back I go through the whole process again.

What an absolute pain!

There must be a better way… Well you will be pleased to know there is!

Full article here:
Remotely copy files to and from your Raspberry Pi (Trevor Appleton)

DynDNS will discontinue free DNS service on May 7, 2014 – here are some alternatives

A little over two years ago, DynDNS took the first steps toward discontinuing their Free DNS service, and now they have announced that it’s really coming to an end for most users. In the 2012 article linked above, the following alternatives were mentioned:

Those that have replaced their router’s firmware with DD-WRT have the option to use DynDNS.org, freedns.afraid.org, ZoneEdit.com, No-IP.com, 3322.org, easyDNS.com, TZO.com, and DynSIP.org (or you can use another “custom” service).

Dynamic DNS service selections in DD-WRT
As time rolls on, the list of available free DNS services changes, but it seems like there are always plenty of choices. Since that 2012 announcement we’ve used the one at freedns.afraid.org and have been quite happy with it. But you want more choices, you say? Then check out this article:

Best Free Dynamic DNS Services (Updated 2014) (GNU Tomorrow)

Just remember that if you want to use a free DNS service, you need to sign up for one of those alternatives before the May 7 cutoff date, preferably long enough before that you have the time to update any configurations that specify the DynDNS address. Don’t put it off until you realize that your dynamic address will be no longer functional in just a few hours, or worse yet, has already ceased to function!

Related:
Dyn Decided To Stop Offering Free Accounts for Dynamic DNS (Dyn)
Dyn discontinues free DynDNS service to clean up its DDNS network (Ars Technica)
Beat it, freetards! Dyn to shut down no-cost dynamic DNS next month (The Register)

Link: How to Set Up WiFi Hotspot in Windows 8

Last year, my roommate moved out of my apartment and ended up taking our wireless router. I didn’t want to wait for twenty-four hours for Amazon to send me my new router, so I decided to turn my PC into a wireless router (or hotspot). My PC, which was wired directly to my modem, turned out to be a great replacement for my router and allowed me to hook up to the internet via WiFi with my laptop and mobile devices.

There are two ways of turning your Windows 8 PC into a wireless router, and I will walk you through both.

Full article here:
How to Set Up WiFi Hotspot in Windows 8 (Make Tech Easier)

Link: How to look up the geographic location of an IP address from the command line

If you want to find out where a given IP address is physically located on earth, there are quite a few online GeoIP lookup services you can try (e.g. geoiptool.com). These online services are mostly powered by freely available GeoIP databases such as those from MaxMind. Besides using such web-based services, there are different ways to query the GeoIP databases, notably via the Linux command line.

In this tutorial, I am going to describe how to geolocate an IP address from the command line in Linux.

Full article here:
How to look up the geographic location of an IP address from the command line (Xmodulo)
Related:
Geo IP Lookup API (ProgrammableWeb)

Link: Power of Linux wget Command to Downloand Files from Internet

Wget is the command line, non interative , free utility in Unix like Operating systems not excluding Microsoft Windows, for downloading files from the internet. Most of the web browsers require user’s presence for the file download to be completed. But wget allows users to start the file retrieval and disconnect from the system. It will download the files in the background. The user’s presence can be a great hindrance when downloading large files.

Full article here:
Power of Linux wget Command to Downloand Files from Internet (LinOxide)
Related:
Wget. Resume, limit rate and run it in background (G. Garron)
Download an entire website with wget (ugly duck)