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 »

If you’re a faithful follower of our blogs, then you are familiar with the “samplicator” described in Michael Patterson’s “Free NetFlow Forwarder or NetFlow Duplicator” blog from May 29th, 2010.

If you’re not familiar with this NetFlow Forwarder application and you have the need for exporting NetFlow packets to multiple (unlimited!) collectors, then you must read his blog.

With switches or routers that do not support NetFlow export to more than one NetFlow collector, or if you have the need to export to more than the typical two collectors, the samplicator is an ideal solution.

Configuration is quick and easy and, if using the config file to list source (exporters) and destinations (collectors), extremely scalable.

Read more »

Over  the last few weeks I have taken a number of support calls from customers who were looking for some assistance configuring their Cisco ASA. So I figured that I would take this opportunity to revisit some older blog subjects.

In my opinion, the easiest way to get NSEL exporting from these security appliances is through the use of the ASDM interface. This simple, GUI-based firewall management tool allows you to quickly configure the Cisco ASA without having to use the cumbersome command-line interface.

And that brings me to the subject of this blog.

Configuring the Cisco ASA using the CLI is really not that much different that configuring NetFlow on any other router or switch. You define your timeout value, flow export destination, and which interface is going to send the export. The difference is that you need to set up a service policy, and access rules that allow the export. As well as define which events are going to get exported and where.

So let’s get started.

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I think I’ve explained this enough times to justify a blog.  :)  The topic of TCP Flags and NetFlow has come up a few times in technical discussions regarding NetFlow collection and analysis.  Read more »

Is cloud computing right for your business?  Will it save your company money?  Gartner Inc.  predicts that by 2012, 80 percent of Fortune 1000 enterprises will pay for some cloud computing service, while 30 percent of them will pay for cloud computing infrastructure.  Inevitably your company will eventually consider cloud services for one or more of the business applications it depends on.  Ask yourself:

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I spent last week at SHARKFEST in Palo Alto, California.  The folks at Cace Technologies did a great job organizing the event.  The kick off presenter was Van Jacobson who was the creator of spiffy utilities like traceroute and tcpdump.  Read more »

Best at NetFlow solutions should provide value way beyond NetFlow Reporting.  As a leader in Flexible NetFlow analysis we recognized this need years ago when we put together the architecture  for Flow Analytics.  Most people use a NetFlow Analyzer to look for problems when someone calls with a connection issue. Read more »

For those of you that missed Plixer’s recent series of webinars, aimed at getting the most out of NetFlow using their latest and greatest NetFlow and sFlow analyzer, there is still hope. A recording of the webinar has been made available online for your viewing pleasure. Just click the image below to watch this 40 minute presentation.

Michael Patterson, Scrutinizer Product Manager, covered a range of topics in this traffic monitoring centric presentation.

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