Alex's Adventures on the Infobahn - t-mobile

SIM Troubles

2009-11-12T10:29:00+00:00

My SIM card is starting to show it's age and refusing to allow my phone to connect to the network. It's not surprising as the thing is fairly old having had it since I first joined T-Mobile. I managed to order a new SIM yesterday throwing only a minor strop when they suggested I pay for it. However despite a final buff of the contacts it totally gave up the ghost this morning. It will be a few days before I'm available for GSM based voice chat again. Of course I remain very contactable by numerous other methods

Bandwidth

2008-06-09T21:27:00+01:00

I had suspected it for a while but I've just confirmed it. T-Mobile is altering my web-pages. I suspect in this case it's nothing overly sinister like Phorm but it is still un-announced tampering with web-pages I request from 3rd party servers.

Transparent proxies have existed almost as long as consumer internet. Usually they just cache frequently accessed files (like the Google logo) and pass them to the browser directly rather than pulling it over the expensive backbone network again. Since a lot of the worlds content doesn't change and popular sites are visited by the majority of your customers this can make a significant saving to an ISP's bandwidth costs.

In the case of T-Mobile the proxy is inserting the line:
<script src="http://1.2.3.8/bmi-int-js/bmi.js" language="javascript">
into every web-page that is served. Further more every image displayed is replaced with a link to an image server somewhere on the 1.2.3.* network and a piece of JavaScript that adds the hover text "Shift+R improves the quality of this image. Shift+A improves the quality of all images on this page." which works as advertised. On the limited resources of a mobile wireless connection this probably makes sense although I'm still a little wary of the fact T-Mobile is modifying my web-pages.

It looks like we won't be able to get broadband via the company (landlords not liking holes in walls) so I'm currently hunting round for broadband deals. I'm beginning to worry about some of the things Virgin Media is up to so I don't think cable is a given.

I've also set-up my virtual server firewall so I can run torrents as and when required. Although I pay per GB it's a fairly honest arrangement (the basic plan starts at 100Gb per month) which is a fair amount to get through. Of course I double the bandwidth usage when I pull the final file to my home machine but I'm fairly sure the ISP's cannot inspect the data thanks to ssh. In fact once connected I may set-up a few Tor nodes just to avoid my ISP tracking my every move. It's not that I don't trust them to abuse the data, oh hang on, that's right, I don't trust them....

Life without Broadband

2008-06-03T17:39:00+01:00

Since the move down we have been without broadband. In fact without a fixed line we are subject to the whims of the mobile phone networks. Hopefully (landlords assent and trees permitting) I'll be able to get super-fast broadband through my works test network in Cambridge. However we have managed in the meantime with other alternatives.

I currently have the T-Mobile's "Unlimited"^* Web'n'Walk package which adds about ï¿½7.50 a month to my monthly contract. I predominately used it for phone browsing using the rather excellent Opera Mini. However it is possible to connect to my phone over a PAN. Once paired you can simply hop on an off at will. On the Mac it's a pretty easy drop down menu "Join Alex's K800i Network" and only slightly more involved from my Linux box. Once connected to the PAN and running a normal dhcp client you get assigned an RFC1918 10.0.0.0 address which I assume it NATed somewhere in the mobile network.

The network filters some ports (typically the ones used by IM clients) but normal web browsing works fine as does ssh which I use to access my email host. In the house we get a 3G signal so we can stream stuff from the BBC's Listen Again service. Measuring a download on my machine I maxed out at around 20kb/s which is perfectly good for audio streams and can handle low res YouTube if you pause it and give it a bit of time to buffer up. I suspect however iPlayer will prove too much for it.

* The only real downside is the persistent use of the word unlimited for a service that quite blatantly is. Since I reset my data counters a few days ago we have already clocked up around 113Mb of data downstream so I can see us hitting the 1Gb "Fair Use" limit if we are not careful. The next price point is 3Gb which doesn't seem much better. Having said that I have yet to get a warning so it could be T-Mobile aren't yet enforcing these limits.