Introduction

This will be the final installment in this NSLOOKUP Primer series. Last time, I talked about MX & SPF TXT records here, but I didn’t touch on DMARC & DKIM TXT records which are also highly encouraged to help add additional layers of security to your email domain.

In my last nslookup blog, I talked about some basic DNS troubleshooting. If you missed it, here’s the link. This time, I wanted to dive in to how I use nslookup for email info gathering and troubleshooting.

So there you are in front of your computer, you know you have internet access, you can ping 8.8.8.8, but your browser isn’t working, and when you try to ping google.com, the name is unable to resolve. You think to yourself “If only I had saved that blog article about nslookup locally, so I didn’t have to depend on the internet to get all that great info!”.

Recently I have been working on a couple of new ISE deployments for our customers and noticed the same ISE alarm (Active directory diagnostic tool found issues) was firing in both environments.

If you don’t have Cisco Umbrella (Formerly OpenDNS) in your environment yet, you should really take a look at it. I’ve had to support on-premise solutions for URL filtering in the past and in my opinion, there are no good ones. No matter the vendor, administration tasks are more complicated than they should be, and they always add a little complexity and more points of failure in the environment....

As threats become more sophisticated, organizations are responding by introducing layers of security that go beyond just securing your internet edge and deploying anti-virus on the desktops. A big challenge with this approach is managing the often disparate systems that make up these layers. Cisco has made huge strides to correct this with their software releases this year, but in reality, it...

Today, the most significant cyber threat is Ransomware – a type of malicious software designed to hold a user’s files (such as healthcare records, financial contracts, software codes, and other documents) for ransom by encrypting them and demanding the user pay a fee to decrypt them. Ransomware attacks use sophisticated infrastructure and resilient techniques to target data and hold critical...