Tuesday, October 17, 2006

iTunes Store

After upgrading to iTunes 7.0.1 and Mac OS 10.4.8 I'm having problems connecting to the iTunes Store. I know there are tons of threads about this and other issues in Apple Discussions, but so far I have not been able to find a solution (or even understand the problem, really). There has got to be something I can change or something my ISP can do to fix this.

I found this article:


Tried my ISPs proxy, and I was able to access the iTunes Store. But I don't want to use a proxy all the time, so this didn't really solve my problem. So I looked further.

The first thing I figured out was that (at least yesterday) a lot of DNS servers were unable to resolve ax.phobos.apple.com.edgesuite.net. I worked around this by using the OpenDNS servers:

Then I added a rule to my firewall (router which is also doing NAT) to allow ICMP type 3 code 4 (and log it). Even though not a single ICMP packet has hit this rule, I was able to access the iTunes Store all of a sudden!

But only sort of. I can access it only from one computer at a time. When I put the "working" Mac to sleep, and re-open iTunes on the other Mac, the store will work on that other Mac. I wake up the first one, can't access the store anymore (only from the second one). Put the second one to sleep, re-open iTunes on the first one, iTunes Store opens on the first computer!

One of the two Macs is a PowerBook. I can access the iTunes Store fine from at work (along with other Macs and Windows PCs at the same time). I also tried another ISP and everything worked perfectly.

Using tcpdump all I see is more or less "normal" HTTP traffic between iTunes and the iTunes Store servers at Akamai.

Needless to say there are no other problems with the network or Internet connection - both Macs can access any website, mail server, etc. at any time and at the same time. The PowerBook is connected via AirPort Express (in bridged mode), the other Mac is a MacMini connected via Ethernet.

Can anyone explain this to me or help me figure out what's going on? Am I running into one of Akamais anti-DOS mechanisms for some reason? Is it possible that my ISP is blocking something like a specific kind of ICMP packets, and this is only now causing problems with the new iTunes version? Is there anything you need to keep in mind as an ISP not to break certain Akamai-hosted services? Routing-wise or anything?

Absolutely any ideas would be greatly appreciated! No matter how far fetched they are..!

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