Vyatta offers hardware and open source software for enterprise-level network infrastructure. Vyatta can turn any 32-bit x86 machine with at least one network interface into a network appliance that handles routing, firewall, and VPN tasks. The company released Vyatta Community Edition 4 in April, with improved scalability and feature enhancements. Large enterprises now have a low-cost alternative to proprietary hardware like the Cisco 7200.
Network latency and bandwidth are the two metrics most likely to be of interest when you benchmark a network. Even though most service and product advertising focuses on bandwidth, at times the latency can be a more important metric. Here's a look at three projects that include tools to test your network performance: nepim "network pipemeter," LMbench, and nuttcp.
The Secure Shell (SSH) and Secure Copy (SCP) make remotely performing system administration and copying files across secure links a painless operation. SSH and SCP use the same SSH protocol to protect network communications, but they rely on users knowing if they want a shell or to copy a file beforehand. You cannot easily use an existing SSH shell connection to a remote machine and just grab one or two files; if you want the files, you'll have to make another SSH connection for the file copy using SCP -- unless you have ssh-xfer.
Network services are one of the fastest growing areas in modern software. However, while network services have much of the convenience of free software, only a minority are available under a free license. In fact, it was only last November that the Free Software Foundation (FSF) released the GNU Affero General Public License for network services. Under these conditions, last week's announcement of the formation of autonom.us, a new activist group "to focus on issues of software freedom in network services," seems overdue. The group's immediate plans are still evolving, but currently, its main goal -- so far as it has one yet -- seems to be as a policy discussion and advocacy group.
These days there are plenty of ways to back up your computer files. The options are easy when you're dealing with one computer -- just back up your files to an external hard drive and forget about it -- but when several machines are involved, each with a different operating system, things can get complicated. If you frequently work on more than one computer, having access to your synchronized files no matter where you are can also be useful. PowerFolder, a backup and file synchronizing service, helps you cover all your bases, no matter what platform or how many computers you're using.
The ability to run both console and graphical programs securely on a remote system using SSH brings you a great deal of freedom. When the communications link to that remote system has high latency, however, running interactive programs such as a text editor on the remote machine can become a real test of your patience. The bcvi project lets you edit files on a remote system using gvim (or another editor) on your local desktop machine to avoid the latency. Even without latency issues, bcvi is a handy tool when you want to use gvim to edit a file on a server that does not have gvim or the X libraries installed.
GNetWatch is a network monitoring and performance testing tool that lets you can see the status of hosts on your network, send ping requests of varying size and quality of service to hosts, and investigate SNMP information. GNetWatch includes support for using Wireshark and nmap to snoop packets and investigate hosts on the network.
Whether you're running Linux, Windows, Cisco, Sun, or other DNS servers, you are at risk from a newly discovered vulnerability. So says Dan Kaminsky, head of penetration testing research at IO Active, who accidently discovered the DNS "design flaw" earlier this year.
Kismet is a wireless "detector, sniffer, and intrusion detection system," and one of the growing list of essential open source tools for computer network security professionals. Kismet runs on any POSIX-compliant platform, including Windows, Mac OS X, and BSD, but Linux is the preferred platform because it has more unencumbered RFMON-capable drivers than any of the others.
A controlled dial-on-demand router is a convenient tool. An uncontrolled dial-on-demand router is not. The Wireshark network protocol analyzer helped me track down the cause of some strange and unwanted dialup connections.
Speedometer shows a graph of your current and past network speed in your console, letting you see your network connection's up and downstream speed and history at a glance. You can also use speedometer directly on a file to monitor the download performance and history of a specific download instead of all network traffic. When displaying the total network traffic, speedometer is sort of like gkrellm, in that you can see the current and past network performance on a graph, but you can easily run it over an SSH connection without having to set up gkrellmd.
NFS version 4, published in April 2003, introduced stateful client-server interaction and "file delegation," which allows a client to gain temporary exclusive access to a file on a server. NFSv4 brings security improvements such as RPCSEC_GSS, the ability to send multiple operations to the server at once, new file attributes, replication, client side caching, and improved file locking. Although there are a number of improvements in NFSv4 over previous versions, this article investigates just one of them -- performance.
SSHMenu adds a button to your GNOME panel that displays a configurable drop-down list of hosts that you have might like to connect to with SSH.
Breathe new functionality into your router with Tomato third-party firmware for popular models of Broadcom-based routers, including popular models manufactured by Linksys.
Protecting servers by placing them behind a firewall is a best-practice methodology for systems administrators, but it's not a panacea: those systems are still visible to network scanners such as nmap and nessus. While services like SMTP and HTTP may need to be accessible to the public, most enterprises also have private internal servers that require external access by traveling support staff. For those users, fwknop, an open source utility that provides single packet authorization, can help sysadmins hide their servers from network nasties.
With autossh, you can monitor your SSH connections and restart them if they stop sending traffic or SSH exits abnormally. This makes autossh perfect for keeping secure port forwarding available.
Purchase a new PC or motherboard soon, and the chances are good that it will come with two built-in network interfaces -- either two Ethernet jacks or one Ethernet and one Wi-Fi. Tossing in a second adapter is an inexpensive way for the manufacturer to add another bullet point to the product description -- but what exactly are you supposed to do with it? If you are running Linux, you have several alternatives.
With vncthumbnailviewer you can see many VNC desktops at once and jump in to control any of them with a double click. vncthumbnailviewer acts like many VNC clients, so it can help you monitor many VNC servers.
KVM (Kernel-based Virtual Machine), Linux's own baked-in virtualization program, has been gaining popularity. Now, Qumranet, the company behind KVM, is releasing a commercial virtual desktop called Solid ICE based on KVM technology.
If you use wireless networking in GNU/Linux with native drivers, then chances are that you benefit from work done by the Rt2x00 project. You may use the MadWifi Atheros drivers with OpenHal, or drivers for the Realtek RTL8180 chipset, but most likely you use one of the drivers developed by the Rt2x00 for Ralink chipsets. In the nearly four years since the project began, its work has moved from having a reputation for bugginess to the point where some of its drivers are now part of the latest Linux kernels. Recently, Linux.com talked to three of the lead developers on the project about where Rt2x00 has been and where it is going.