Networking

Understanding Firewalld in Multi-Zone Configurations

Stories of compromised servers and data theft fill today's news. It isn't difficult for someone who has read an informative blog post to access a system via a misconfigured service, take advantage of a recently exposed vulnerability or gain control using a stolen password.

SNMP

How would you find out how much RAM is free on your Linux desktop? That's a really easy question with a lot of answers—free, any of the implementations of top and Glances all are valid responses.

Papa's Got a Brand New NAS

It used to be that the true sign you were dealing with a Linux geek was the pile of computers lying around that person's house. How else could you experiment with networked servers without a mass of computers and networking equipment? If you work as a sysadmin for a large company, sometimes one of the job perks is that you get first dibs on decommissioned equipment.

Applied Expert Systems, Inc.'s CleverView for TCP/IP on Linux

One of the most important characteristics of the contemporary data center, notes Applied Expert Systems, Inc. (AES), is that an ever-increasing amount of the traffic is between servers. Realizing the resulting need to facilitate improved server-to-server communications, AES developed CleverView for TCP/IP on Linux v2.5 with KVM Monitoring.

The Tiny Internet Project, Part III

In a previous article, I introduced the Tiny Internet Project, a self-contained Linux project that shows you how to build key pieces of the internet on a single computer using virtualization software, a router and free open-source applications.

The Peculiar Case of Email in the Cloud

Most of the time when I start a project, or spin up a virtual server, it's done in my own basement "server farm". Not too many years ago, if I wanted those services to be public, I'd simply port-forward from my static IP into my personal machines. Or, perhaps I'd set up a name-based virtual host as a reverse proxy if I needed to expose a Web app.

Varnish Software's Hitch

Making life easier for the 2.2 million Web sites that deploy the Varnish Cache HTTP engine is the point of Hitch from Varnish Software.

Build a Large-Screen Command Center with the RPi 2

When the folks who make the Raspberry Pi made good on their plan to release a multi-core version of the tiny computer with 1GB of RAM earlier this year, I saw it as the perfect opportunity to put the single-board Linux box to work—real work—in our company's network operations center.

Securi-Pi: Using the Raspberry Pi as a Secure Landing Point

Like many LJ readers these days, I've been leading a bit of a techno-nomadic lifestyle as of the past few years—jumping from network to network, access point to access point, as I bounce around the real world while maintaining my connection to the Internet and other networks I use on a daily basis.

Roll Your Own Enterprise Wi-Fi

As you can tell by my Wi-Fi focus in The Open-Source Classroom this month, I really love wireless networking. I've implemented wireless solutions for schools on a shoestring budget, and I've helped plan campus-wide rollouts of redundantly controlled enterprise solutions.

Using tshark to Watch and Inspect Network Traffic

Most of you probably have heard of Wireshark, a very popular and capable network protocol analyzer. What you may not know is that there exists a console version of Wireshark called tshark. The two main advantages of tshark are that it can be used in scripts and on a remote computer through an SSH connection.

Concerning Containers' Connections: on Docker Networking

Containers can be considered the third wave in service provision after physical boxes (the first wave) and virtual machines (the second wave). Instead of working with complete servers (hardware or virtual), you have virtual operating systems, which are far more lightweight.

My Network Go-Bag

I often get teased for taking so much tech hardware with me on trips—right up until the Wi-Fi at the hotel, conference center or rented house fails. I'm currently on vacation with my family and some of our friends from Florida, and our rental home has a faulty Wi-Fi router. Thankfully, I have a bag full of goodies for just this occasion.

Non-Linux FOSS: Flaky Connection? Mosh it!

Most of the work I do on computers is done via the command line. When I'm off on vacation somewhere, that means shoddy Wi-Fi and cell-phone tethering. Because cell-phone tethering gets expensive quick (I also have three teenage daughters with which I share a data plan), I try to use free Internet whenever I can. The biggest hassle with that method is dealing with broken SSH sessions.