Defrag your hard drive!

As mentioned in Scott’s blog,  “Getting the most from your NetFlow and sFlow Analysis Tool“, disk fragmentation can be the primary cause for slow performance in running NetFlow reports.

Due to the large volume of data stored when collecting NetFlow packets, disk I/O may already be pushed to the limits on your server.  Add to that a highly fragmented disk drive and you might as well go hang out at the water cooler while you wait for your report to run.

Here’s an example of an extremely fragmented disk:

As Scott mentioned in his blog, “With hard drives, blue is a good thing, red is bad. Ideally we would want to see mostly blue and white.”

But, on the other hand,  if you don’t have anything better to do with your time, if using Scrutinizer has so streamlined your network monitoring that you need to slow your day down a bit, then please, leave your disk fully fragmented and take a break!

Otherwise, if you prefer your Netflow reporting to complete in your lifetime, then defrag!

And in the spare time that you now have to kill, you can monitor excessive Facebook traffic and other odd traffic patterns on your network, or read our blogs to learn how to enable Flexible NetFlow, or give us a call to find out what else our NetFlow solution can do for you.

- Joanne

Our NetFlow and sFlow Analyzer receives  data collected over a 1 minute time interval  per flow, and can store up to 100 000 conversations (flows) per device. One limitation in NetFlow monitoring today is the amount of disk space needed to store the collected network traffic information. Especially, if one’s intent is to hold on to that information  for a certain period of time. In this blog I will try to help you understand how Scrutinizer archives data. In addition I will talk about the NetFlow Calculator, which can be a helpful tool for estimating the disk space needed on your NetFlow analyzer server. Read more »

There is no doubt that flow technology is revolutionizing network monitoring. In this  NetFlow/J-Flow/IPFIX/sFlow era, there is no need to settle with only knowing utilizations on the network. Besides, little analysis can be done in monitoring bandwidth only anyways.

Scott wrote a blog earlier that made a valid point: “A Network Administrator’s abilities are only as good as his awareness of what happens on his network.” In harmony with that statement, it’s beneficial to have useful tools to be able to collect that traffic information.

Recently, I learned that J-Flow is supported for the Juniper SRX series Gateways. I thought this might be good information for people who want to start monitoring flows on this type of device, especially our NetFlow and sFlow Analyzer users, since it can also process J-Flow packets. Below are some sample commands taken from Juniper’s Knowledge Base which walks you through your J-Flow configuration. Read more »

Has your company adopted a social media policy yet?  Social Networking sites such as Facebook, Twitter, and MySpace are increasingly being considered threats for at least a couple big reasons:  security risks and traffic risks.

Use of social medias at work can pose security risks to the company’s intellectual property through an employee’s personal communication habits.  On occasion, attackers assume the identity of someone who hasn’t actually joined sites like facebook.  Then the attacker determines who this person’s friends or schoolmates are and sends friend requests.  Once befriended, the attacker has personal information of users and can make targeted attacks.  Social engineering tactics like this can be very effective, especially when they get users to start sharing URLs leading to malicious sites or spoofs of actual businesses such as your local bank.  In some countries, criminals are not banned from using sites like facebook when they are incarcerated, as The Washington Times recently reported.

Use of social medias at work can also pose network traffic problems for the company.  Read more »

Okay, back to the basics. We’ve been working with Cisco NetFlow technology for many years now, but what is NetFlow?

NetFlow is a traffic profile monitoring technology developed by Darren Kerr and Barry Bruins at Cisco Systems, back in 1996. At that time, network monitoring mostly consisted of seeing how much traffic was traversing your network, but did not include what that traffic was.
Read more »

A couple weeks ago a customer reported an issue where, apparently, our NetFlow and sFlow Analyzer was not seeing traffic from Vyatta Core 6. This being the second time the issue is reported to us, I was encouraged to talk about it.

In general, whether it is a collector issue or an exporter issue, from a tech support view point, I would say that the Scrutinizer web interface does a great job signaling what might be preventing proper network traffic analysis. This customer’s Scrutinizer web  interface seemed to be saying: “There are flows coming from Vyatta, but there is nothing to report on”. Whenever he restarted the Netflow collector, everything would work well for a short period of time, then in the Scrutinizer web interface, while the Vyatta widget would  still be green, indicating that it is eventually sending netflow, its interfaces would turn yellow (no data to report for this interface) for a few hours before the collector completely stops.

What we found

His Vyatta was sending NetFlow packets that were not properly constructed. Looking at their content, we found that they did not contain flow information, but packet headers only, which gives Scrutinizer nothing to report on.

Recommendations

Unfortunately I am not a Vyatta expert. If you are experiencing a similar issue, I recommend consulting the Vyatta community, or try other software base routing/firewall systems such as nProbe, pfsense, Quagga,etc. I can’t tell you much about pfsense or Quagga; however, once in a while we get calls from nProbe users, it supports NetFlow and seems to work well for them.

Lawrence Technological University is among Michigan’s largest independent colleges and also Michigan’s first completely wireless laptop campuses, as well as one of the largest wireless networks in the Midwest.

This recently published case study demonstrates how successful network traffic analysis can be performed using NetFlow reporting with Scrutinizer NetFlow Analyzer. Monitoring NetFlow exported from devices such as Cisco ASA’s, routers, switches, and numerous other NetFlow compatible devices simplifies the task of managing your network, whether wired or, in LTU’s case, fully wireless.

Read more »

Over the past couple months, I’ve posted a series of blogs that help highlight some of Scrutinizer’s best features, its strengths and weaknesses and why it might be worth your time in evaluating.

I’d like to devote this blog to the effort of making an easy to read article that might assist you in making an informed decision about the many networking monitoring tools available. Let us know if you have any questions.

Read more »

Is this your Network Control Center?

Wouldn’t it be nice to see all of your Top Interfaces, from all of your Network Analysis Tools on a single interface? If the answer to that question is YES, then Plixer International has the solution that you have been looking for.

Using the latest release of our NetFlow and sFlow Analysis Tool, you can configure a Central Interface to see multiple Scrutinizer servers in a single interface.

It is as easy as creating and then adding a custom gadget to your MyView screen.

Read more »

Looking for a reliable bandwidth utilization NetFlow billing system?  If you are already using Cisco NetFlow technology for network monitoring and management, then it’s just one more simple step to extending that to bandwidth billing.

Using the Service Provider Module for Scrutinizer NetFlow & sFlow Analyzer and a customized Billing Module, you can monitor the bandwidth usage of your customers and also provide  a data export to your current billing application.

The Service Provider Module allows you to restrict your customers to view specific devices and/or interfaces in Scrutinizer. The “Scrutinizer v7 NetFlow and sFlow Analyzer: Using the Service Provider Module” blog has more information on this module’s features.
Read more »