Stefan Fouant

Author Archives: Stefan Fouant

Juniper SRX Tips :: Uniform Security Policy Modification

Often there are instances where we want to affect all security policies configured on an SRX device.  For example, let's say that we have thousands of policies configured on our firewall, and we want to enable logging for every single policy.  Obviously this would take some time if we were to do this manually on each and every individual policy, so an easier way is desired.

In ScreenOS we have the concept of a Global zone which acts as a container encompassing all zones, but to date, Junos does not support a similar functionality on the SRX. Furthermore, the Global zone doesn't affect existing policies but rather is way to apply a consistent policy to all Inter-zone and Intra-zone traffic that doesn't match any of the existing policies.

However, despite all of this, there is in fact a methodology we can use to uniformly modify all of the existing security policies on our box, in a manner that is actually much more powerful than what is accomplished in ScreenOS with the Global zone.

Let's take a look.  First, let's say we have some policies that we would like to enable logging on:

root@ce-1# show security policies
 Continue reading

JNCIE Tips from the Field :: Summarization Made Easy

Today we'll start with a series of articles covering tips and techniques that might be utilized by JNCIE candidates, whether pursuing the JNCIE-SP, JNCIE-ENT, or even the JNCIE-SEC.  The tips and techniques I will be covering might prove to be useful during a lab attempt but could also be used in real-world scenarios to save time and minimize configuration burden in addition to eliminating mistakes that might otherwise be made.  I want everyone to understand that what I am about to write is simply a technique.  I am not divulging any materials or topics which are covered under NDA.

NOTE: For full disclosure, I must reveal that I am an employee of Juniper Networks in their Education Services department.  As such, I take the responsibility of protecting the content and integrity of the exam as well as the certification credentials very seriously.  I would never reveal anything which would allow a candidate to have in-depth knowledge of any specific topics or questions that may appear on the exam.  Not only that, I worked REALLY, REALLY hard to achieve my JNCIE certifications, and I believe everyone else should too! It's certainly more rewarding that way too don't you think?!

So Continue reading

Day One Guide: Junos Tips, Techniques, and Templates 2011

small-junos-tips-2011I am happy to announce that Juniper has just released a new Day One Guide entitled "Junos Tips, Techniques, and Templates 2011". For this particular Day One Guide, Juniper Networks Books and J-Net joined forces and requested the best and brightest Junos tips and techniques from the Junos user community.  In fact, the book was created after a thorough selection process which included reviewing over 300 submitted tips by over 100 individuals on the J-Net community boards at forums.juniper.net.

I am honored that Juniper accepted my contributions and decided to include them in this guide.  My contribution "Automatically Allow Configured BGP Peers in a Loopback Firewall Filter" covers how to configure a Junos prefix-list in conjunction with the apply-path features to parse a configuration and then dynamically build a list of matching prefixes for use in a firewall filter.

Outside of my meager contribution, this guide is chock full of dozens of useful tips and techniques and is an indispensable guide for anyone involved in managing Juniper platforms on a daily basis.

Junos Tips, Techniques, and Templates 2011 can be ordered on Amazon in hardcopy or Kindle edition, and is also available as a free download in PDF format. Enjoy!

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IETF Provides New Guidance on IPv6 End-Site Addressing

I've always been at odds with the recommendation in RFC 3177 towards allocating /48 IPv6 prefixes to end-sites.  To me this seemed rather short-sighted, akin to saying that 640K of memory should be enough for anybody.  It's essentially equivalent to giving out /12s in the IPv4 world which in this day and age might seem completely ridiculous, but let us not forget that in the early days of IPv4 it wasn't uncommon to get a /16 or even a /8 in some cases.

Granted, I know there are quite a few more usable bits in IPv6 than there are in IPv4, but allocating huge swaths of address space simply because it's there and we haven't thought of all the myriad ways it could be used in the future just seems outright wasteful.

So you can imagine my surprise and also my elation last week when the IETF published RFC 6177 entitled 'IPv6 Address Assignment to End Sites'.  In it, the general recommendation of allocating /48s to end-sites that has long been the defacto standard since the original publication of RFC 3177 in 2001 has finally been reversed.

It seems that sanity has finally prevailed and Continue reading

IPv4 Address Exhaustion Causing Harmful Effects on the Earth

Today, I received a very disturbing email on NANOG which was forwarded from a recipient on the Global Environment Watch (GEW) mailing list.  If this is true, we all need to take steps to make an orderly and smooth transition to IPv6 as quickly as possible, lest we suffer from the harmful effects described in this email.


From: Stephen H. Inden
To: Global Environment Watch (GEW) mailing list
Date: Fri, 1 Apr 2011 00:19:08 +0200
Subject: IPv4 Address Exhaustion Effects on the Earth

At a ceremony held on February 3, 2011 the Internet Assigned Numbers Authority (IANA) allocated the remaining last five /8s of IPv4 address space to the Regional Internet Registries (RIRs). With this action, the free pool of available IPv4 addresses was completely depleted.

Since then, several scientists have been studying the effects of this massive IPv4 usage (now at its peak) on the Earth.

While measuring electromagnetic fields emanating from the world's largest IPv4 Tier-1 backbones, NASA scientists calculated how the IPv4 exhaustion is affecting the Earth's rotation, length of day and planet's shape.

Dr. Ron F. Stevens, of NASA's Goddard Space Flight Center, said all packet switching based communications have some effect on the Earth's  Continue reading

Preparation Tips for the JNCIE-ER Exam

As many of you know, Juniper is currently undergoing a massive effort to update their certification program.  The previous track in 'Enterprise Routing' is now changing to 'Enterprise Routing and Switching' incorporating elements from the previous certification track in addition to some new elements essential to Enterprise switching such as Spanning-Tree, VLANs, Layer 2 Security, as well as High Availability features like Virtual Chassis.  We can expect that a lot of the topics like Firewalling and NAT will be removed from this exam as these topics will more properly appear in the Security track.

Although the new JNCIE-ENT certification is planned to be released in August 2011, there are many of you who are currently pursuing the existing JNCIE-ER before time runs out.  The good news is that Juniper plans to continue offering the existing JNCIE-ER exam until October 2011 so there is still quite a bit of time for those who are interested in attaining this certification.

There probably isn't a single day that goes by that I don't receive an email inquiry from someone currently pursuing the JNCIE-ER with a request to learn from my experiences and test preparation techniques.  And although this exam Continue reading