Category: networking

Link: How to Limit the Network Bandwidth Used by Applications in a Linux System with Trickle

Have you ever encountered situations where one application dominated you all network bandwidth? If you have ever been in a situation where one application ate all your traffic, then you will value the role of the trickle bandwidth shaper application. Either you are a system admin or just a Linux user, you need to learn how to control the upload and download speeds for applications to make sure that your network bandwidth is not burned by a single application.

Full article here:
How to Limit the Network Bandwidth Used by Applications in a Linux System with Trickle (Tecmint)

Link: Linux Basics: How To Check The State Of A Network Interface Card

Normally, we can easily check the state of a network interface card like whether the cable plugged in to the slot or the network card is up or down in Graphical mode. What if you have only command line mode? Ofcourse, you can turn around the system and check for the cable is properly plugged in, or you can do the same easily from your Terminal. Here is how to do that. This method is almost same for Debian and RPM based systems.

Full article here:
Linux Basics: How To Check The State Of A Network Interface Card (Unixmen)

Link: Securing Your Asterisk VoIP Server with IPTables

Now that you have set up your personal Asterisk® server (see Tutorial), it’s time to secure it. I can’t overstate the importance of this step. Without it, you could be leaving your server’s VoIP ports open for anyone on the Internet, which may cost you a lot of money.

Full article here:
Securing Your Asterisk VoIP Server with IPTables (Lin’s Tech Blog)

Link: Prepare Your Pi To Send Mail Through Gmail

Suppose you have set up your Raspberry Pi to do some stand alone work. It would be nice if it could email you occasionally, for instance if there’s something wrong. Or it may send you status updates on the work it’s doing. For this you could use the SMTP server of your ISP. However, if your Pi isn’t stationary and roams around on multiple networks, this is not an ideal situation. If you connect your Pi to a different network, operated by a different ISP, chances are that you can’t send any messages.
A better solution would be to use a Gmail account for that. In this description I presume you already have a Gmail account. If not, you can get one for free at www.gmail.com. You may also decide to create a new one for your Raspberry Pi. The same account can even be shared among multiple Raspberry Pies. Rumour has it though that Gmail will only allow 100 mails sent per account per day. So if you share your account among too many machines you may start hitting the ceiling soon.

Full article here:
Prepare Your Pi To Send Mail Through Gmail (SB-Projects On Line)

Link: Why DNS in OS X 10.10 is broken, and what you can do to fix it

For 12 years, the mDNSResponder service managed a surprisingly large part of our Mac’s networking, and it managed this task well. But as of OS X 10.10, the mDNSResponder has been replaced with discoveryd, which does the same thing. Mostly. Here are some strange networking problems we’ve observed since installing 10.10:

Full article here:
Why DNS in OS X 10.10 is broken, and what you can do to fix it (Ars Technica)

Link: Use VnStat to Monitor Network Traffic from Linux Command Line

Network traffic monitoring not only helps administrators detect root causes of traffic related issues, like network overloading, but also helps them keep a tab on traffic flow to and from the Internet. Overall, it’s an important task that requires a dedicated and an effective software.

For Linux, there are many GUI-based network traffic monitoring tools, but if you are looking for a command line-based utility, vnstat is worth trying out. In this article, we will discuss the basics of the command along with the features it provides.

Full article here:
Use VnStat to Monitor Network Traffic from Linux Command Line (Make Tech Easier)

Link: How to block unwanted IP addresses on Linux efficiently

You may want to block IP addresses on your Linux box under various circumstances. For example, as an end user you may want to protect yourself from known spyware or tracker IP addresses. Or when you are running P2P software, you may want to filter out connections from networks associated with anti-P2P activity. If you are a sysadmin, you may want to ban access from spam IP addresses to your production mail server. Or you may wish to block web server access from certain countries for some reason. In many cases, however, your IP address block list can grow quickly to tens of thousands of IP addresses or IP address blocks. How can you deal with it?

Full article here:
How to block unwanted IP addresses on Linux efficiently (Xmodulo)

Link: Spider a Website with Wget – 20 Practical Examples

How do I download an entire website for offline viewing? How do I save all the MP3s from a website to a folder on my computer? How do I download files that are behind a login page? How do I build a mini-version of Google?

Wget is a free command line program – available for Mac, Windows and Linux (included) – that can help you accomplish all this and more. What makes it different from most download managers is that wget can follow the HTML links on a web page and recursively download the files.

Full article here:
Spider a Website with Wget – 20 Practical Examples (Digital Inspiration)

Link: How to Setup a Complete Mail Server (Postfix) using ‘SquirrelMail’ (Webmail) on Ubuntu/Debian

Creating a mail server on Linux powered machines can be one of the most essential things that every system administrator needs to do while configuring his servers for the first time, if you don’t know what it means; it’s simple, if you have a website like “example.com”, you can create an email account like “username@example.com” to use it to send / receive emails easily instead of using services like Hotmail, Gmil, Yahoo Mail.. etc.

In this article, we’ll learn how to do so by installing the Postfix with “SquirrelMail” webmail application and its dependences on Debian/Ubuntu machines.

Full article here:
How to Setup a Complete Mail Server (Postfix) using ‘SquirrelMail’ (Webmail) on Ubuntu/Debian (Tecmint)