Migrations

In December and January we’ve completed some service migrations, we’ve been auditing some services and some new staff members have joined our team, which makes this a good time to clarify what it means to have a migration completed. Although … Continue reading

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The Business Case for Single Sign on

The intended audience for this document is appliance and software product vendors. The background is we’d like appliance vendors to support Single Sign On mechanisms¬†natively. SSO? Yes, we already support LDAP and Active Directory against which to authenticate logins to … Continue reading

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NTP service changes Nov 2012

Over the next month we’ll be doing some work to consolidate our NTP stratum 2 and 3 services into what will hopefully (subject to antenna installation) be a four system stratum 1 service. All historical IP addresses and DNS names … Continue reading

Posted in Best Practices, General Maintenance, NTP | 1 Comment

ASA 5505 Transparent Mode DHCP and Memory fun

We have a customer who uses a Cisco ASA 5505 in transparent mode to protect a small LAN. They did the right thing and took out SmartNet cover, but the reseller botched something and the TAC wouldn’t play with them … Continue reading

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MAC Flaps – why are they bad?

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 | 4 Comments

Implementing Spanning Tree

Some of the IT support staff have taken the recently published IPv6 trial conditions quite seriously and we’ve already had two queries with regards to the spanning tree requirement. These queries aren’t disputing it but rather asking about specific behaviour … Continue reading

Posted in Best Practices, IPv6 | 1 Comment

Changes in the core

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

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Logging from iptables

We recently had a problem to troubleshoot on the wireless network, which was quickly resolved through simply having effective logging from iptables. In case you didn’t know, iptables has a LOG target which can direct messages to the local syslog … Continue reading

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Special-use IPv4 addresses and domains

You’ve probably heard of RFC1918 – the well-known set of networks assigned for use in off-Internet, private networks. In fact there’s a much more useful RFC, one which lists not only these but a group of other networks and subnets … Continue reading

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