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

Nagios and IPv6 made easy with the mknagconf configuration generator

This article describes how to install Nagios3 and my mknagconf tool and how to use them. It should take about 30 minutes to install nagios3 and mknagconf and set it up to monitor a few hosts. The following has been tested with Ubuntu 10.04, 10.10 and 11.04 on an amd64 platform.

Nagios3 is an excellent monitoring engine, but the stock Nagios has some limitations in regard to dual-stack hosts. In the Nagios universe, one host is one ip address, and a secondary ipv6 address would require an extra host definition.

The Nagios packages which you are about to install have been patched to support this concept "one host = 1 ipv4 address + 1 optional ipv6 address". The mknagconf script makes it easier to maintain your Nagios installation. mknagconf takes small short, and simple definition files, parses them and generate the configuration files for Nagios. This will be explained after installing the required software.

Step 1: Install all dependencies
apt-get install apache2-mpm-prefork apache2-utils apache2.2-bin 
apache2.2-common bsd-mailx libapache2-mod-php5 libapr1
libaprutil1 libaprutil1-dbd-sqlite3 libaprutil1-ldap
libgd2-noxpm libjpeg62 libperl5.10 nagios-plugins-basic
php5-common postfix ssl-cert nagios-plugins-standard
nagios-plugins-extra git-core make
Step 2: obtain PGP key, configure apt Continue reading

Common Services VRF MPLS and BGP

One of the most common MPLS VPN topologies is the Common Services simply put, it provides the most control of Branch traffic and filtering. MPLS VPNs are among one of today’s favorite and for good...

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The OSPFv2 Network Summary LSA Type-3

Well, what is the Network Summary LSA? It’s an LSA flooded throughout the backbone area, which describes networks in other areas. Originated only by ABRs (Area Border Routers) and not flooded...

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Troubleshooting OSPFv2 Neighbors (Part2)

This will seem very similar to t he last post, again going on simple. Things that can be overlooked if one is not careful, doesn’t look at everything with a magnifying glass, and becomes over...

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IPv6 Tutorial: The overview

I will start from the beginning; two weeks ago I wrote a post claiming that IPv4 is depleting and IPv6 is coming soon; and since we are considering deploying IPv6 soon in our network, I thought it might be useful to write about IPv6 migration and transition strategies. Although, this is important but I think [...] No related posts. Related posts brought to you by Yet Another Related Posts Plugin.

vPC and VSS features and Comparison

Seems like other than IPv6 allot of the talk lately (in the Datacenter anyways) is about MEC, or multi-chassis etherchannel. Using something like this in the aggregation part of the Datacenter not...

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How Network Operators can cooperate: the NLNOG RING

In December 2010 I started a project with a few friends to make life for network engineers in the Netherlands better.

I noticed that there are a lot of friendly 'shell access' exchange deals between dutch network operators. This makes it easier for parties to debug network issues and troubleshoot from the outside. A point of view outside your network is absolutely essential, seeing what others see is a useful thing for a variety of network problems. Well known examples are "it works for even numbered ip address, but not for odd numbered ip address via this and this route".

The NLNOG RING tries to do this in a more organized way, basically the deal is "donate 1 machine, and gain access to all other machines in the ring". So far already 10 organisations are participating.

How useful is the ring exactly? A very nice example is executing a traceroute from ten different autonomous systems: nlnog ring example.

More information about the NLNOG RING can be found on the website we've launched today:

Ticket #16 – Repubished

Next ticket, Ticket 17, which will be about IGP and EEM will be published on, then it will be republished here again. ... • R1 is configured with redundant bidirectional connection between R3 and R4's Lo0. ... • R1 is using NAT to allow connectivity, exposing R3 as and 

L2 is now in the TS section

L2 is now in the TS section of the R&S lab: ...L2 is in the TS workbook from day one because the TS workbook was written not just to prepare the students for the TS section of the lab, but also to summarize, test and sharpen the skills of the CCIE R&S students. Please notice that although the TS section is the first section of the lab, I recommend to practice the TS section after doing technology focused labs and moc labs.

[IPv6] Subnetting – Wait, we still need to do that?

Subnetting, in short, can be thought of as an adjustable “slide rule” that tells the network infrastructure the logical size of a sub-network, or subnet. This is useful if you know how many IP addresses you’ll to suit the needs of a predetermined number of PCs, so you can plan the size of your subnets to match that requirement. With IPv4, subnet masks are used to determine how big the subnets are.

Troubleshooting OSPFv2 Neighbors (Part 1)

Tackling one of the simplest OSPFv2 adjacency problems to the trained eye. Yet, it’s really incredible how often it can escape even the most seasoned veteran. Getting right to the point,...

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New Cisco IOS releases in an RSS feed

Over the last few days we've been spending some time on an RSS feed generator which can help you stay on top of new IOS releases. It takes regular expressions as input and can be useful for a quick search or generating an RSS feed for your favorite news reader.

The database is built upon a public md5 database Cisco publishes roughly every week. I cannot vouch for the accuracy of this information.

You can find the quick search & rss generator at

LISP + GETVPN as alternative for DMPVN+OSPF+GETVPN

Originally LISP was developed to address the issues and concerns raised by the growth of the internet routing table, but LISP turns out to possess appealing features that can be of interest to Service Providers like my friends at InTouch.

At the Cisco NAG2010 conference in San Jose I talked about using LISP as a transport mechanism instead of regular manual GRE tunnels or a DMVPN design. I believe that provisioning and debugging a LISP based virtual private network will be easier and simpler than current approaches.

Some fair warnings are in order here: this setup runs on beta IOS and NXOS images, this design and the configuration syntax are very likely to change a little with every IOS release, for Cisco's LISP implementation is under very active development. The most important aspect of this design is that it's not a multi-tenant architecture. Multi-tenancy will probably be available in a few months, after which I'll post an updated version with more comments on the specifics.

View the slides online at slideshare: LISP+GETVPN or download the PDF from my website: Job_Snijders-InTouch-LISP_GETVPN.pdf.