Year: 2013

When Cisco’s IGMP Snooping stops working for a few seconds

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Editor’s note: this post related to when traffic is forwarded for a few seconds even if IGMP Snooping is working. Not for instances where you loose all multicast traffic when activating IGMP snooping. For those cases, please remind to activate at least one IGMP querier somewhere on the network, and the corresponding IP address (no IP address, no querier….). Introduction IGMP snooping is a feature derived from the regular IGMP standard since version 1, however it works on a mostly independent manner, as it only works at the local switch level. Multicast traffic, without IGMP snooping enabled, works as a simple …

Semantic MediaWiki By Example – A Datacenter IP Network Manager

Decision Support Systems / SMW / sysadminOne Comment

One of the most common tasks on one datacenter, is the management of the IP Network: assigning IP addresses, creating networks (and subnetworks), creating hosts and setting hostnames. On smaller scale, having a spreadsheet may do the trick, but as datacenters grow (both physical and virtual), both in number as in complexity it quickly underperforms. Even, with all virtualization, this task won’t get any simpler, it will actually get more and mode complicated, because at least, it needs to be performed twice: at the physical hardware level, and at guest level. So, there is the need to create a tool …

SMW’s Semantic Result Formats – Jqplotchart/Jqplotseries format – A guide

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One of the most interesting aspects of Semantic Mediawiki is the data to chart integration, done though the Semantic Result Formats extension, and using the Jqplotchart and Jqplotseries formats, which in itself are based on jqPlot. However, it’s documentation and code examples are not as thorough as one can expect. Requirements To start with, just make sure you have all the proper extensions installed, namelly: Mediawiki version prior to 1.21(*) (1.20.6 is OK) Semantic Mediawiki 1.8 – Both SWM and SRF are undergoing some changes, so it’s better to keep a specific version. Semantic Results Formats 1.8 (*) There are some reports …

Bugzilla access control – Allowing one group to create and access all bugs and another only to access it’s own bugs

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Now, something completely different: Bugzilla. Bugzilla is one of the most used bug tracking systems worldwide. It’s stable, somewhat customizable, and suits most possible uses, where software development is concerned, and sometimes, also outside the software world. Now, one of the aspects where is falters the most is on user access control. It isn’t because it doesn’t work, but because it is awkward and counter intuitive, until you get used to it… Let’s look at 3 scenarios: All users can create and edit bugs. Please make sure there is at least some kind of access control at network level. To …

LDAP and Apache Basic Auth – how it works and how it doesn’t work

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Let’s imagine you work on an organization which uses Active Directory (just kidding, is there anyone who doesn’t …?) and on which people are forced to comply with draconian security policies, such as changing you strong password every N days (replace N for any number less than 30… why don’t people understand that it is harder for people to memorize a new strong password, than machines to brake them). Anyways, having a central location for all authentication purposes is, from any point of view, a good idea, even if coming from Microsoft :). If your organization already has in place …

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