|By Joshua Drake||
|September 20, 2001 12:00 AM EDT||
(LinuxWorld) -- As I write this column, the world suffers infestation by yet another Internet worm, and again the worms are intended to attack Microsoft-based machines. Fortunately for my company, we don't run any Microsoft-based machines, but the Nimda worm still affects us.
Nimda eats our bandwidth since other companies sharing our subnet are running infectious Windows 98, NT, and 2000 machines. These diseased, ill-maintained beasts from the land of insufficient light are now trying to infest our stable, secure, long running, easy-to-use, well-behaved Linux machines. (Can you tell I'm a bit irritated?)
This has led me to start editing some of our firewall rules, and in the process, consider that, as we have recently migrated to the 2.4 kernel, some people may be interested in how to create a Linux 2.4 kernel-based firewall quickly.
The following examples do not create the perfect firewall. What I describe is designed to give a system administrator a little piece of mind by fortifying a machine from obvious attacks.
The 2.2 version of the Linux kernel used the ipchains application to control the firewall. For standard firewalling, ipchains is a decent solution. We still use it on some of our machines, and there is still a positive argument for 2.2 kernel-based firewalls, because the 2.4 kernel still has some stability issues under heavy load.
Those heavy load issues aside, the 2.4 kernel provides a wealth of networking capabilities 2.2 lacks. These include stateful firewalling and solid quality-of-service options. One could argue that the 2.4 kernel, and its iptables firewall code, enables a person to build intricate firewalls capable of competing with the likes of CheckPoint.
The command to execute iptables is simple: as root type
iptables. The execution of the previous command should display output similar to the following:
[root@jd root]# /sbin/iptables iptables v1.2.1: no command specified Try `iptables -h' or 'iptables --help' for more information. [root@jd root]#
If you would like an output of the available options when using the iptables you can pass the
-h flag during program execution. The
-h command will result in output similar to the following:
[root@jd root]# /sbin/iptables -h iptables v1.2.1 Usage: iptables -[ADC] chain rule-specification [options] iptables -[RI] chain rulenum rule-specification [options] iptables -D chain rulenum [options] iptables -[LFZ] [chain] [options] iptables -[NX] chain iptables -E old-chain-name new-chain-name iptables -P chain target [options] iptables -h (print this help information)
Commands: Either long or short options are allowed. --append -A chain Append to chain --delete -D chain Delete matching rule from chain --delete -D chain rulenum [...]
For this article, I am not going to go into exhaustive explanation of all the iptables options. If you want an advanced introduction, to iptables I suggest the Linux 2.4 Packet Filtering HOWTO (see resources below).
When developing a personal or desktop firewall I practice a very simple philosophy. If you aren't going to use it, don't open it. For example, if you are not hosting a Web site, do not open port 80. If you are not using telnet (and there is not a good reason on this Earth to use telnet), do not open port 23!
In an effort to follow my philosophy, the quickest way to port protection nirvana is the following iptables chain:
/sbin/iptables -A INPUT -p tcp --syn -j DROP
The previous statement will allow you to, as the user of the computer, performed all your normal Internet activities. You will be able to browse the Web, ssh out, or chat with a colleague on ICQ. On the other hand, the outside world, when trying to connect to your Linux box via TCP/IP, will simply be ignored. This is a reasonable solution for most Linux computers.
However, one of the benefits of Linux is its remote management capabilities. One of the more popular ways that people remotely manage Linux machines is via the SSH (see resources) suite. SSH typically operates on port 22 and thus, we would need to enable connections to port 22, while keeping the rest of the connections closed. This can be done with the following iptable chains:
/sbin/iptables -A INPUT -p tcp --syn --destination-port 22 -j ACCEPT /sbin/iptables -A INPUT -p tcp --syn -j DROP
It is probably not a good idea to let the world connect to your machine on port 22 unless you run a public server. Therefore, we can limit which machines can connect to port 22 by modifying the iptable chain, and adding the
-s option. The
-s in this example specifies what source address is allowed to connect to the server.
/sbin/iptables -A INPUT -p tcp --syn -s 192.168.1.110/32 --destination-port 22 -j ACCEPT /sbin/iptables -A INPUT -p tcp --syn -j DROP
The addition of the
-s 192.168.1.110/32 will enable only the remote machine with the IP address of 192.168.1.110 to connect to your protected host.
When you create an iptables-based firewall, each chain (for simplicity's sake, each line) will be read sequentially. Thus, it is possible to have the previous configuration of only one machine having rights to connect via SSH, and to run a public Web server. This could be done with the following commands:
/sbin/iptables -A INPUT -p tcp --syn -s 192.168.1.110/32 --destination-port 22 -j ACCEPT /sbin/iptables -A INPUT -p tcp --syn --destination-port 80 -j ACCEPT /sbin/iptables -A INPUT -p tcp --syn -j DROP
This is just an introduction to iptables, but it does give a reasonable representation of the bare essentials for a firewall. If you are currently running Linux with kernel 2.4, it may be a good time to review what your firewall looks like. On a closing note, if you are still running kernel 2.2 and you are looking for a good firewall configuration utility, take a look at Guard Dog (see resources).
SYS-CON Events announced today that SOA Software, an API management leader, will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. SOA Software is a leading provider of API Management and SOA Governance products that equip business to deliver APIs and SOA together to drive their company to meet its business strategy quickly and effectively. SOA Software’s technology helps businesses to accelerate their digital channels with APIs, drive partner adoption, monetize their assets, and achieve a...
Oct. 31, 2014 07:15 PM EDT Reads: 2,107
SYS-CON Events announced today that Aria Systems, the recurring revenue expert, has been named "Bronze Sponsor" of SYS-CON's 15th International Cloud Expo®, which will take place on November 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Aria Systems helps leading businesses connect their customers with the products and services they love. Industry leaders like Pitney Bowes, Experian, AAA NCNU, VMware, HootSuite and many others choose Aria to power their recurring revenue business and deliver exceptional experiences to their customers.
Oct. 31, 2014 06:30 PM EDT Reads: 2,173
SYS-CON Events announced today that AgilePoint, the leading provider of Microsoft-centric Business Process Management software, will exhibit at SYS-CON's 2nd International @ThingsExpo which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. AgilePoint is the leading provider of Microsoft-based Business Process Management (BPM) software products, has 1,300+ on-premise and cloud deployments in 25+ countries and provides the same advanced BPM feature set as J2EE vendors like IBM and Appian for the Microsoft .NET native environment. AgilePoint customer...
Oct. 31, 2014 05:00 PM EDT Reads: 1,256
The Internet of Things (IoT) promises to evolve the way the world does business; however, understanding how to apply it to your company can be a mystery. Most people struggle with understanding the potential business uses or tend to get caught up in the technology, resulting in solutions that fail to meet even minimum business goals. In his session at Internet of @ThingsExpo, Jesse Shiah, CEO / President / Co-Founder of AgilePoint Inc., will show what is needed to leverage the IoT to transform your business. He will discuss opportunities and challenges ahead for the IoT from a market and tec...
Oct. 31, 2014 04:00 PM EDT Reads: 1,601
SYS-CON Events announced today that Utimaco will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Utimaco is a leading manufacturer of hardware based security solutions that provide the root of trust to keep cryptographic keys safe, secure critical digital infrastructures and protect high value data assets. Only Utimaco delivers a general-purpose hardware security module (HSM) as a customizable platform to easily integrate into existing software solutions, embed business logic and build s...
Oct. 31, 2014 03:00 PM EDT Reads: 1,962
One of the biggest challenges when developing connected devices is identifying user value and delivering it through successful user experiences. In his session at Internet of @ThingsExpo, Mike Kuniavsky, Principal Scientist, Innovation Services at PARC, will describe an IoT-specific approach to user experience design that combines approaches from interaction design, industrial design and service design to create experiences that go beyond simple connected gadgets to create lasting, multi-device experiences grounded in people’s real needs and desires.
Oct. 31, 2014 02:00 PM EDT Reads: 1,827
SYS-CON Events announced today that TeleStax, the main sponsor of Mobicents, will exhibit at Internet of @ThingsExpo, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. TeleStax provides Open Source Communications software and services that facilitate the shift from legacy SS7 based IN networks to IP based LTE and IMS networks hosted on private (on-premise), hybrid or public clouds. TeleStax products include Restcomm, JSLEE, SMSC Gateway, USSD Gateway, SS7 Resource Adaptors, SIP Servlets, Rich Multimedia Services, Presence Services/RCS, Diame...
Oct. 31, 2014 09:00 AM EDT Reads: 1,706
Samsung VP Jacopo Lenzi, who headed the company's recent SmartThings acquisition under the auspices of Samsung's Open Innovaction Center (OIC), answered a few questions we had about the deal. This interview was in conjunction with our interview with SmartThings CEO Alex Hawkinson. IoT Journal: SmartThings was developed in an open, standards-agnostic platform, and will now be part of Samsung's Open Innovation Center. Can you elaborate on your commitment to keep the platform open? Jacopo Lenzi: Samsung recognizes that true, accelerated innovation cannot be driven from one source, but requires a...
Oct. 31, 2014 09:00 AM EDT Reads: 3,384
The Internet of Things will greatly expand the opportunities for data collection and new business models driven off of that data. In her session at Internet of @ThingsExpo, Esmeralda Swartz, CMO of MetraTech, will discuss how for this to be effective you not only need to have infrastructure and operational models capable of utilizing this new phenomenon, but increasingly service providers will need to convince a skeptical public to participate. Get ready to show them the money! Speaker Bio: Esmeralda Swartz, CMO of MetraTech, has spent 16 years as a marketing, product management, and busin...
Oct. 31, 2014 09:00 AM EDT Reads: 2,340
Things are being built upon cloud foundations to transform organizations. This CEO Power Panel at 15th Cloud Expo, moderated by Roger Strukhoff, Cloud Expo and @ThingsExpo conference chair, will address the big issues involving these technologies and, more important, the results they will achieve. How important are public, private, and hybrid cloud to the enterprise? How does one define Big Data? And how is the IoT tying all this together?
Oct. 31, 2014 08:45 AM EDT Reads: 1,995
We certainly live in interesting technological times. And no more interesting than the current competing IoT standards for connectivity. Various standards bodies, approaches, and ecosystems are vying for mindshare and positioning for a competitive edge. It is clear that when the dust settles, we will have new protocols, evolved protocols, that will change the way we interact with devices and infrastructure. We will also have evolved web protocols, like HTTP/2, that will be changing the very core of our infrastructures. At the same time, we have old approaches made new again like micro-services...
Oct. 31, 2014 07:00 AM EDT Reads: 1,670
SYS-CON Events announces a new pavilion on the Cloud Expo floor where WebRTC converges with the Internet of Things. Pavilion will showcase WebRTC and the Internet of Things. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devices--computers, smartphones, tablets, and sensors – connected to the Internet by 2020. This number will continue to grow at a rapid pace for the next several decades.
Oct. 30, 2014 05:30 PM EDT Reads: 2,216
The only place to be June 9-11 is Cloud Expo & @ThingsExpo 2015 East at the Javits Center in New York City. Join us there as delegates from all over the world come to listen to and engage with speakers & sponsors from the leading Cloud Computing, IoT & Big Data companies. Cloud Expo & @ThingsExpo are the leading events covering the booming market of Cloud Computing, IoT & Big Data for the enterprise. Speakers from all over the world will be hand-picked for their ability to explore the economic strategies that utility/cloud computing provides. Whether public, private, or in a hybrid form, clo...
Oct. 30, 2014 05:30 PM EDT Reads: 1,453
SYS-CON Events announced today that Gridstore™, the leader in software-defined storage (SDS) purpose-built for Windows Servers and Hyper-V, will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Gridstore™ is the leader in software-defined storage purpose built for virtualization that is designed to accelerate applications in virtualized environments. Using its patented Server-Side Virtual Controller™ Technology (SVCT) to eliminate the I/O blender effect and accelerate applications Gridsto...
Oct. 30, 2014 02:00 PM EDT Reads: 2,610
SYS-CON Events announced today that Red Hat, the world's leading provider of open source solutions, will exhibit at Internet of @ThingsExpo, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Red Hat is the world's leading provider of open source software solutions, using a community-powered approach to reliable and high-performing cloud, Linux, middleware, storage and virtualization technologies. Red Hat also offers award-winning support, training, and consulting services. As the connective hub in a global network of enterprises, partners, a...
Oct. 30, 2014 12:15 PM EDT Reads: 2,089
As the Internet of Things unfolds, mobile and wearable devices are blurring the line between physical and digital, integrating ever more closely with our interests, our routines, our daily lives. Contextual computing and smart, sensor-equipped spaces bring the potential to walk through a world that recognizes us and responds accordingly. We become continuous transmitters and receivers of data. In his session at Internet of @ThingsExpo, Andrew Bolwell, Director of Innovation for HP’s Printing and Personal Systems Group, will discuss how key attributes of mobile technology – touch input, senso...
Oct. 30, 2014 12:00 PM EDT Reads: 1,774
The Internet of Things (IoT) is making everything it touches smarter – smart devices, smart cars and smart cities. And lucky us, we’re just beginning to reap the benefits as we work toward a networked society. However, this technology-driven innovation is impacting more than just individuals. The IoT has an environmental impact as well, which brings us to the theme of this month’s #IoTuesday Twitter chat. The ability to remove inefficiencies through connected objects is driving change throughout every sector, including waste management. BigBelly Solar, located just outside of Boston, is trans...
Oct. 30, 2014 11:00 AM EDT Reads: 2,201
Connected devices and the Internet of Things are getting significant momentum in 2014. In his session at Internet of @ThingsExpo, Jim Hunter, Chief Scientist & Technology Evangelist at Greenwave Systems, will examine three key elements that together will drive mass adoption of the IoT before the end of 2015. The first element is the recent advent of robust open source protocols (like AllJoyn and WebRTC) that facilitate M2M communication. The second is broad availability of flexible, cost-effective storage designed to handle the massive surge in back-end data in a world where timely analytics...
Oct. 30, 2014 08:00 AM EDT Reads: 1,637
Internet of @ThingsExpo Silicon Valley announced on Thursday its first 12 all-star speakers and sessions for its upcoming event, which will take place November 4-6, 2014, at the Santa Clara Convention Center in California. @ThingsExpo, the first and largest IoT event in the world, debuted at the Javits Center in New York City in June 10-12, 2014 with over 6,000 delegates attending the conference. Among the first 12 announced world class speakers, IBM will present two highly popular IoT sessions, which will take place November 4-6, 2014 at the Santa Clara Convention Center in Santa Clara, Calif...
Oct. 30, 2014 07:30 AM EDT Reads: 2,309
From a software development perspective IoT is about programming "things," about connecting them with each other or integrating them with existing applications. In his session at @ThingsExpo, Yakov Fain, co-founder of Farata Systems and SuranceBay, will show you how small IoT-enabled devices from multiple manufacturers can be integrated into the workflow of an enterprise application. This is a practical demo of building a framework and components in HTML/Java/Mobile technologies to serve as a platform that can integrate new devices as they become available on the market.
Oct. 29, 2014 02:15 PM EDT Reads: 2,085