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This manual was followed, to the letter, and copied verbatim from a self proclaimed Digital Nut
Many thanks. Back-up here since I gathered from the forum thread that lead to this link the dude is hosting this blog using Apache server on a Raspberry PI at home. Note that it's specifically for an HTTP server so a number of things are irrelevant (you can skip 1 and 2).
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TalkTalk DSL-3680 Router

After switching to TalkTalk, and installing their DSL-3680 Router, the first thing that I noticed was that I was unable to access my Raspberry Pi Apache web server, which serves various things including this personal blog, environmental data feeds and IP cameras. Even trying the private IP addresses I was directed to the router administration page. So after a few frustrating days and lots of reading I managed to get everything to play nice together, so I've written it up in case it helps others facing the same problems, but see the warning at the bottom first.

1) Changing the Admin page port

By default, the router admin page uses port 80 (the same port that we need for our HTTP connection) so we need to change it to a different port, say port 8080.

If the port number is not changed, whenever your IP is called, it will be directed to your admin page instead of your server!

To change the router admin port, go to your router web interface and log-in, then click 'Advanced' and select 'Advanced' from the menu ribbon.

Select 'Remote Management' from the left menu, and then tick 'Enable Remote Management', followed by changing the default port from 80 to 8080, and Apply Settings. At this stage, don't panic if your admin page becomes unresponsive! remember, you've now changed the port setting, so to access your admin page, use the same IP address, except add :8080 to it. So in my case, my admin page is 192.168.1.1:8080 Log out of the Admin page, then log back in, and untick 'Enable Remote Management' again, and 'Apply Settings'. That now frees up port 80 to use as a HTTP gateway to the server.

2) Port forward

Whilst in the router 'Advanced' section, select 'Port Forwarding' from the left menu, and add entries to direct ports 80 and 443 to the private IP address that you want incoming services to access (The IP address of your server).

3) Activate loopback on your router

Telnet is not always installed in Windows by default, sometimes it needs to be added via the Windows Control Panel, but once installed, start the client and Telnet into your router via port 23.

> o 192.168.1.1 23

If you are unable to gain Telnet access to your router, ensure that your router has Telnet enabled by changing the default option in your router web interface 'Advanced' > 'Remote Management' > 'Remote Access Control'.

Once you have a connection, enter your router password, and check to see if loopback is activated already;

D-Link> ip nat loopback

it will probably say no! but to activate it;

D-Link> ip nat loopback on

and check the 'ip nat loopback' again, and you should see that loopback is enabled.

If you are already running a website, you can now check to see you can access your site or Localhost (but don't reboot your router yet - see section 4 below). 4) Surviving a reboot

OK, well we have successfully activated loopback, but if the router is now rebooted, it will return back to it's default of loopback off, so we need to change a configuration file - autoexec.net which is read upon a router reboot.

To do so, and whilst still in Telnet;

D-Link> sys edit autoexec.net

This is a inbuilt really basic text editor which is not the easiest to use, but here goes;

  1. Upon each press of 'n' the editor will reveal consecutive lines of the router's autoexec.net file, so keep pressing 'n' until you get to the line 'ip rip merge on'
  2. Press 'i' to insert a new line
  3. Type 'ip nat loopback on' (the system puts a colon in first but ignore it, it's only an indicator of changed code).
  4. If you make a hash of it, press 'q' to exit without saving, and start afresh, otherwise;
  5. Hit the Enter key and 'x' to save and exit.

Now, every time your router reboots, it will read the autoexec.net and enable loopback.

Warning!

If you try this, you do so at your own risk, as TalkTalk may not (almost definitely won't!) give you any support, and a replacement router would be at your own expense. So if you are unsure or unfamiliar with this - don't do it!

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A general primer on Virtual Worlds can later be found somewhere as well. I'm for now, assuming the concept of these persistent, computer generated three dimensional environments is understood. But while many in the field of Virtual Worlds for Teaching and Learning gravitate to or have gravitated to Linden Lab's Second Life I'd like to point out another, equivalent technology: Open Simulator.
Open Simulator is an Open Source Virtual World Server that can be compared to the Apache Web Server. It can run as a stand alone version on an off-the shelf (MS Windows) computer or laptop and even from a USB stick. But a hosted instance can also be connected to others in a Hypergrid which is a network of Virtual World Servers connected in a distributed network. There are a number of reasons for this technology to sometimes be preferred. Here's a summary of a few differences:

  1. Linden Lab is a service provider and Second Life is externally hosted. This means that for instance:
    1. A dependency on this service and it's provider is embedded.
    2. Access to the Virtual World depends on internet connectivity. Lag is inevitable [1].
    3. User, access and content control [2].
    4. Potential network vulnerabilities. Every open port is one too many.
    5. Required updates.
    6. Costs associated with the service.
    7. Licenses and copyrights associated with the service.
    8. Second Life is primarily a social environment where users (or residents) predominantly engage with each other.
  2. Open Simulator is a stand alone, independent Virtual World server (and can as such be compared with Apache). It can (but doesn't have to) be connected with other servers in a grid (decentralised system). This means that, for instance:
    1. The server and any viewer can run on any off the shelf computer and even from a usb stick.
    2. There are no costs associated with the software. Even the software used for creating content is Free and Open Source. Payment is for knowledge and experience which in turn can be distributed.
    3. It's Open Source. There are no license fees or subscriptions. Combined with the above this means that every user can have their own MRI scanner on a USB stick.
    4. There is no embedded need for access and content control.
    5. There are no embedded (network) vulnerabilities.
    6. There are no embedded required updates.

[1] Every service provider aims to maximise profits. This means that Second Life operates at it's bare minimum (servers, bandwidth)

[2] It's easy to control access to an individual estate but not that easy to control access from. Your (under-age student) user might end up hanging out with a BDSM club owner.

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but, in short, Open Simulator allows every user to have their own Virtual World Learning Environment. It runs on an off-the-shelf laptop. The complete package, both server and viewer can even be accessed from a USB stick. This means that every user can have a copy of a Virtual World with for instance an MRI scanner and the environment it lives in. The user can access it any time, any place, without internet connection or network / IT department involvement. The provider, that is you reading this, pays for knowledge and experience. And those USB sticks.

What's the catch?

Sounds too good to be true, right? So there must be a catch. Here's a few:

  1. The Technology is (relatively) young. Not everything is completely reliable. But I've worked with Open Simulator for years and I can deliver. What can't be taught in the Virtual World just has to be practised in the real world. It's not a replacement, it is a time saving addition.
  2. Users (sales staff, support staff, end users) need to be trained using the technology. The learning curve is steeper for some than others. But this generation, accustomed to computer games, have little problem getting used to it. It is senior staff and management that find it hard to embrace this novel environment (and not for the first time either). I've lectured this in a university. I can train those who will become the teachers.
  3. There's not a lot of people truly proficient in the range of skills required to create an environment like this. To make this personal; where do you stand if I walk under a bus? Solution: have a young ambitious member of staff shadow me and learn everything I do. I believe in education. I've lectured this in a university. It's called contingency planning.
  4. It was hyped (see the Gartner Hype Cycle) and is only now slowly climbing out of the trove of disillusion. But there are probably at this time still more people with negative experiences than positive.
  5. I can't do this as a single individual, as an external provider. You'd need to hire me.

What's in it for me?

Competitive Edge. There's some 6 main providers of this high end radiology equipment. The market runs into billions. A single MRI scanner sells for around 1.5 million. If you sell one more you've already paid for me. This is an additional tool for both marketing and sales. There's more to this. Research options. Reputation. But I'll save that for when we go for lunch. The elevator has reached it's destination.

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