I originally had a great deal of difficult reconciling the differences amongst ITIL Change Management, Incident Management, and Problem Management. Having researched on the subjects and understanding them better now, I’ve tried to put the concepts together using a UML class diagram to capture my understanding and to keep it imprinted. Similarly, I wanted to differentiate the various categories of changes (Standard, Emergency, Normal) using an easy to understand & self-explanatory manner – a UML Activity Diagram!
I have always had to create (professional-looking) UML diagrams using Visio-like icons. You’ve got to admit that showing a bunch of boring UML boxes hardly interests anyone less technical (like anyone whose designation has the words “manager” or “director”). This is actually possible in Astah! I’ve created a template for future projects that allows me to produce logical network diagrams that look like the following: To create this diagram, you need to do the following: Assign various icons to stereotypes. I created the following for my use: Create a new UML Deployment Diagram Every element in the diagram is created as a Node The nodes are subsequently assigned the appropriate <<stereotype>>. E.g. Internet is <<internet>>, WebZone FW is <<firewall>>, Web LB is <<loadBalancer>> Ensure the “Icon Notation” is set to “Customized Icon” for each node Instead of the boring boxes, the corresponding icons automatically gets displayed!
Problem/ Issue I recently had the opportunity to look into the following issue: the organisation, like most others, have segregated the network into at least 2 zones (DMZ and internal) the DMZ hosts the web servers while the internal zone hosts the application and database servers a requirement is that an application in the internal zone needs to access a web service in the public internet allowing direct HTTP traffic from the internal zone to the public network is not an option With the above constraints, a forward proxy could have been an option. However, the internal-zoned application may not be able to support a forward proxy. As such, a reverse proxy would be the solution. Existing Solution The existing in-place solution follows: host a custom-written web service (acting as a proxy) in the DMZ to connect to the public network. The application in the internal zone will connect to the DMZ-hosted web service This custom-written web service will then connect to the pub...
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