Designing and Using DMZ Networks to Protect Internet Servers
Naturally, you want to carefully restrict traffic from the outside world to the DMZ. But it's equally important to carefully restrict traffic from the DMZ to your internal network (to protect it in the event that a DMZ host is compromised) and from the DMZ to the outside world (to prevent a compromised DMZ host from being used to attack other networks).
It goes without saying that you'll probably want to block all traffic from the Internet to internal hosts. (You may or may not feel a need to restrict traffic from the internal network to the DMZ, depending on what type of access internal users really need to DMZ hosts and how much you trust internal users.) In any event, your firewall-security policy will be much more effective if your firewall can distinguish between legitimate and phony source-IP addresses. Otherwise, it might be possible for an external user to slip packets through the firewall by forging internal source IPs.
By default, most firewalls don't have this functionality enabled (the feature is usually called something like anti-IP-spoofing. Even if your firewall supports it, you'll probably have to configure and start it yourself. It's well worth the effort, though.
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
Free to Linux Journal readers.Register Now!
- SUSE LLC's SUSE Manager
- My +1 Sword of Productivity
- Managing Linux Using Puppet
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- Non-Linux FOSS: Caffeine!
- Tech Tip: Really Simple HTTP Server with Python
- Doing for User Space What We Did for Kernel Space
- SuperTuxKart 0.9.2 Released
- Rogue Wave Software's Zend Server
- Parsing an RSS News Feed with a Bash Script
With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide