VPN NAT Changes

Posted on 9 January 2012 by Guy Morrell

What is this post about? We are planning to make a minor change to the way our VPNs NAT clients. For those who are interested, this blog post explains why and how we are doing this. Please note that these … Continue reading →

Posted in Cisco Networks, Documentation, General Maintenance, VPN | Leave a comment

How to generate graphs with gnuplot

Posted on 2 September 2011 by Guy Morrell

Introduction During the JANET Carrrier Ethernet Trial we we took part in, I needed to plot some data based on our testing and came across gnuplot. It is actually quite simple to use and we’re doing so more and more … Continue reading →

Posted in Documentation, Productivity, Trend Analysis, Wireless | 1 Comment

OUCS Backbone Network Naming and Numbering Conventions

Posted on 15 August 2011 by Guy Morrell

Introduction This blog post is intended to help ITSS in Oxford to better understand how the centrally provided network fits together with their own local networks. It is also hoped it will assist them in assessing the impact of any … Continue reading →

Posted in Backbone Network, Cisco Networks, Documentation, General Maintenance | 1 Comment

Budget High Availability ASA testing

Posted on 24 May 2011 by Guy Morrell

The problem We’re looking at setting up a management network behind a couple of ASAs. My requirements and prerequisites are: No L2 end to end VLANs through the core. That is bad and wrong. A total site failure at one … Continue reading →

Posted in Cisco Networks, Firewall | Leave a comment

MAC Flaps – why are they bad?

Posted on 4 February 2011 by Guy Morrell

What is a MAC Flap? A MAC Flap is caused when a switch receives packets from two different interfaces with the same source MAC address. If this makes no sense, perhaps a  quick summary of how switching at layer 2 … Continue reading →

Posted in Backbone Network, Best Practices, Cisco Networks | Tagged | 2 Comments

Changes in the core

Posted on 8 March 2010 by Guy Morrell

On Tuesday 2nd March we made two significant changes in the Core. Both are inline with current Cisco best practice are have been implemented as part of our Backbone ‘feature update’ project. VTP We have moved to using VLAN Trunking … Continue reading →

Posted in Backbone Network, Best Practices, Cisco Networks, Services | Leave a comment

Wireless Application Firewall

Posted on 26 August 2009 by Guy Morrell

In order to prevent ‘Location Independent Network’ abuse resulting in C&D orders landing on the desks of ITSS, we’ve recently added an Allot Netenforcer to the backend of eduroam and OWL. It will be configured to block P2P traffic and … Continue reading →

Posted in Wireless | Tagged | Leave a comment