Anyone who is (lucky enough to be) on my msn contact list (and signed in during my work hours) will have seen something curious happening over the past week since I returned back to work.
For those of you not, basically I was signing in and out constantly with a frequency of say every 10 minutes. This oddly made is surprisingly hard to hold a conversation with someone. But more problematic was that not only was msn dropping out but the whole internet was. You could hardly even achieve a successful Google search.
And this wasn’t just a problem for me, but for everyone here at TheFARM.
The first assumption was that it was something wrong with our ISP, we’re not on a super faster internet connection, and no one had problems outside of work, so it seemed like a logical assumption… right?
Well it turns out that when you assume you make an ass out of you and me (ha, see what I did there! :P). The problem wasn’t our internet, in fact the problem could be blamed on one individual, yep you guessed it, me :(.
Turns out that when I wasn’t on the network everything was fine, everyone could use the web, chat on msn, do what ever they wanted, but as soon as I plugged in, BAM, the internet died. So after a bit of detective work (mostly by Shannon) it was concluded that my computer was doing something nasty to the network. So we cracked out a copy of Wireshark and decided to do some detective work with packet sniffing.
Immediately it was obvious what was happening, I was flooding our DNS server with requests, requests that the DNS server was returned as invalid. The requests kept looking for a URL along the lines of tcp.members.mac.com and after a bit of searching it turned out that that URL is related to the Apple MobileMe service. So Shan asked if I was signed up with MobileMe, to which I responded “I don’t believe so”, but it turned out again I was wrong, I had signed up to MobileMe, but it must have been when I first got my iPhone. When you get an iPhone you can sign up with a 60 day trail, something I must have done (hey, it said I was signed in, guess I signed up at some point :P). After doing some quick math I concluded that it was ~60 days since I got my iPhone when we first started having internet problems (the last working week last year).
I instantly signed out of MobileMe, and low and behold the DNS flooding stopped happening!
Thank you Apple for producing a service which is capable of bringing down an office network, you’ve just made sure I strongly consider not purchasing MobileMe in the future!
Oh and I’m never going to live this down at work, Shan isn’t a fan of Apple so this is just adding fuel to the fire!