It’s been a long journey, and we’ve learned a lot along the way. We’ve created a robust firewall configuration that includes proactive and reactive defenses, as well as incorporated advanced port knocking protections to guard our restricted services more strongly. Everything up until now, however, has been strictly IPv4; if your server is also on the IPv6 network, it is still wide-open to all! This post will be shorter than the others in this series, because all we’re doing is adapting our current IPv4 rules to IPv6.
If you’ve followed along with the previous posts so far, you’ve already got yourself a solid firewall configuration: We only allow traffic to the ports we’re actually running services on; we proactively guard against common attacks; and we reactively blacklist the bad guys. But there’s still more we can do, and in this part we’re going to use a technique called port knocking to make it even more difficult for anyone to access our SSH service.
In Part 1, we set up a very basic firewall. Part 2 added some basic additional protections to our server. Part 3 started to get more proactive against certain types of potential attacks. In this part, we’re going to introduce the
recent module, and leverage it to make our firewall reactive to shield us from even more attacks.
In Part 1, we created a very basic firewall setup that only allowed traffic to the services our server actually provides. In Part 2, we took it up a notch by proactively blocking traffic that had no business reaching our server in the first place. Now, we’re going to augment our configuration to be even more proactive, introducing the
limit module to slow down potential attackers.
In Part 1 of this series, we set up a very basic firewall that essentially just restricts what ports we can connect to without doing much else to defend our server. In this part, we’re going to build from there and add additional restrictions to block a substantial portion of potentially malicious traffic that simply has no business being on the internet at all.
This is the first in a series of blog posts that will walk you through how to set up a secure firewall to help protect your internet-facing Linux machines. All you have to know to be able to follow along is how to log into your machine and run command line programs, including how to use
sudo; everything else we do will be explained along the way.
With the httpoxy vulnerability making headlines in the security circles right now, I decided to get more aggressive in guarding my own sites against it, specifically by outright blocking any such requests. Turns out, it’s not hard to do at all!
The Raspberry Pi is an amazing little piece of hardware, an entire computer in a form factor not much larger than your wallet. While not boasting specs to make it the envy of your household, it is nonetheless quite the capable little device, and with just a couple of simple accessories you can even use it to run your entire home network!
Microsoft has released update KB3087126 to address some important security flaws in OWA. Upon installing this update into my Exchange 2013 CU9 environment, however, I encountered some significant problems that left some of my servers in a completely non-working state!