# UNIX

## The value of measurements: Network Latency

There is no shortage of network telemetry data that can be collected, recorded, graphed, and stored for cross reference and triage. Not one to be underestimated, latency at a can be incredibly powerful when leveraged for baseline and deviation notification. As I have eluded to in the past, there are many tools in this space. I have written about a few of them in detail and touched on others in passing. Regardless of the tool, the data is powerful and the instrumentation they provide will only…

## DNS - the treasure trove of information your ISP can see

In recent years, the nature of privacy on the internet has become a very important topic amongst those concerned with the now lack of net neutrality. The de-facto mechanism for dealing with privacy has been to “SSL all the things”, which I am very much in favor of. What many do not realize, though, is that simply using SSL for the traffic that transits a given ISP still leaves a wealth of thick, rich, delicious personal data still easily available to your ISP to harvest, sell, and do…

## Creating an internal span port inside proxmox OVS

In the last few years I have moved all of my virtualization to proxmox and docker. Seeing as I like to look at packets because I am a closet security guy, and being as I have been working off-and-on on a security project in recent times, I wanted to be able to span a port not only from a hardware switch, but also within my software switches. I had been using linux bridge, which I am not a fan of, so when I started down this path I did not look hard to find a way to do so under that platform.…

## NIX4NetEng 6 DNS, ad-blocking, and quality of experience

The sixth [and arguably very overdue] installment of my NIX4NetEng series, this began as an overly complex diatribe about DNS. As it evolved, I realized that DNS is so complex and far reaching that it could never be contained in one meager post. DNS is a powerful tool. It has existed for so long that many that have never had the responsibility of running an authoritative or recursive resolver may take for granted the extensive reach of a tool so engrained in the fabric of the internet that it is…

## Monitoring VMware ESXi with SNMP and Cacti

VMWare is a powerful tool, and monitoring is a critical service. How does one monitor such an integral piece of infrastructure, and what do they monitor it with? There are powerful commercial ways of monitoring VMware, however, for those with existing SNMP based systems in place, specifically cacti, there are options. To that end, I’ll set aside my strong distaste for SNMP [yet again], because those are for a larger, less useful series of posts.

## NIX4NetEng 5 - GeoIP tools

Sometimes in networking and security it becomes necessary to do lookups of location data on IP addresses and prefixes. On my Mac I use homebrew to manage packages, but most of these tools are available with thetypocal apt, yum and port package management systems. For this post, I’m going to shift gears and show the install on my mac:` sliver:~ buraglio\$ brew install geoip ==> Downloading https://downloads.sf.net/project/machomebrew/Bottles/geoip-1.6.3.mavericks.bottle.tar.gz…

## NIX4Neteng 4: POODLE and SSLv3, scanning and updating

With the recent release of the POODLE SSLv3 vulnerability, folks are scrambling around trying to figure out what runs what and where.  Running a handful of things that do SSL, I was obligated, both personally and professionally, to figure out an easy way to drill down and figure out what does what and then fix the vulnerable services.  When there are a lot of devices, this can seem like a daunting task, and it is if you’re trying to do it manually.  This is where NMAP comes into play.…

## sonrancid: A [very] basic RANCID module for sonicwall

I know, I know, I’m always saying that you don’t need a firewall. That’s mostly to get your attention to push my agenda of sane security architecture, I do actually believe that firewalls are appropriate in a great many use cases and I’ve managed them big and small ranging from Juniper SRX 5800 clusters to tiny purpose built BSD distros on custom hardware. I even managed Checkpoint and gauntlet firewall back in the 1990s. And Novell Border manager….good…

## NIX4NetEng 3: IP Addressing and Subnet Tools

IP addressing and subnetting is a common interview subject. I assert that memorizing these things is useful for learning the concepts but ultimately futile in that it is time consuming and inefficient use of engineering time when tools can be utilized to accomplish the same goals in less time with fewer errors. Honestly, I gave up doing this kind of work manually around 10 years ago and have never regretted it, and in actuality, I’d probably struggle to do it at this point because…

## NIX4NetEng 2 IPv4/6 address investigation tools - whois + dig

I don’t care what your vendor alignment of choice is, Cisco, Juniper, Brocade, Alcatel….it doesn’t matter. At one point or another you’re going to need to bird dog an address to see where it’s coming from, who owns it, what it’s DNS name is or what path you’re taking to get to it.  We’ve already talked about BGP tools, they’re a great choice for checking routes across the internet. Hunting down addresses is an interesting one, though, as…