Q: When I attempt to preview a song on iTunes, it begins to play but stops after 5 seconds

I completely understand your reasoning and it's solid. Let me offer another thought.

Based on a little research (very little), it seems that metrics.apple.com provides the initial 7 seconds of the 90 second song, it then hands off to an akamai server (which makes perfect sense since akamai can geographically serve up media to customers and save Apple a ton of money).

The problem is that Google returns the correct IP for akamai and Comcast doesn't (see the nslookup results below). (Again my guess here, since I neither work for Apple nor Akamai).

I suspect that since flushing the resolver cache forces clients to retrieve the addresses again, that sometimes they get valid servers and sometimes they don't. I agree with you that simply running ipconfig/flushdns shouldn't be a permanent solution. It would be intermittent at best.

metrics.apple.com

----------------------------------------

Record Name . . . . . : metrics.apple.com

Record Type . . . . . : 5

Time To Live  . . . . : 651

Data Length . . . . . : 8

Section . . . . . . . : Answer

CNAME Record  . . . . : appleglobal.112.2o7.net

Above is the resolver cache for Comcast. I believe metrics.apple.com provides the first 7 seconds, Apple grabs some stats about what we're previewing, and hands off to Akamai for the rest of the song....only Comcast can't seem to find the correct location for Akamai and consequently there is no entry in the resolver cache and no music after 7 seconds.

Google, however, finds the Akamai server and the hand-off is successful, the resolver cache shows the akamai server and I get to hear the remaining 83 seconds.

a5.mzstatic.com

----------------------------------------

Record Name . . . . . : a5.mzstatic.com

Record Type . . . . . : 5

Time To Live  . . . . : 1

Data Length . . . . . : 8

Section . . . . . . . : Answer

CNAME Record  . . . . : a5.mzstatic.com.edgesuite.net

See below that Comcast returns a different (wrong?) IP for the same host at akamai.

> server 75.75.75.75

Default Server:  cdns01.comcast.net

Address:  75.75.75.75

> a5.mzstatic.com

Server:  cdns01.comcast.net

Address:  75.75.75.75

Non-authoritative answer:

Name:    a5.da1.akamai.net

Addresses:  23.15.8.233

          23.15.8.227

Aliases:  a5.mzstatic.com

          a5.mzstatic.com.edgesuite.net

> server 8.8.8.8

Default Server:  google-public-dns-a.google.com

Address:  8.8.8.8

> a5.mzstatic.com

Server:  google-public-dns-a.google.com

Address:  8.8.8.8

Non-authoritative answer:

Name:    a5.da1.akamai.net

Addresses:  208.44.23.122

          208.44.23.129

Aliases:  a5.mzstatic.com

          a5.mzstatic.com.edgesuite.net

Right track?

Okay ...

I also have Verizon Fios for my ISP.  I made the DNS changes to Google (8.8.8.8) as preferred server and Verizon (4.2.2.1) as alternate server, flushed the DNS Resolver Cache, as suggested ... and, VOILA!!!  I can now stream full 90 second song previews, again!!

As I noted earlier in this thread, I tried the DNS flush, before, unsuccessfully - but, had not made the server changes, prior to the flush.  What bottman posted, above, about Comcast, appears to be correct for Verizon Fios, also ... at least it worked for me, anyway!

Thanks for the "legwork!"

I have been having the same problem for about a month now. Apple had just blown me off for a separate issue so I figured I wouldn't have much luck complaining about this one. There is another thread that talks about this as well and they assured that it was not a DNS problem but solely an Apple/itunes problem. I agree because this preview stoppage has effected both my computers in the exact same way at the exact same time. BTW I'm using Windows 7. I will try the suggestions though. It's a shame that we have to resort to this sort of remedy.

I did the flush and started a preview. It played all the way through. However, I tried two more songs and those stopped about 12 seconds in. DNS flush is a no go. I have Windows 7 Ultimate and Comcast.

IronMike, what DNS server(s) are you using?

The flush has no permanent effect.  You have to change the DNS server that you are using to a server that looks up the address successfully for iTunes to keep playing.

I'm not sure. I'm not nearly as smart as I sound. However, to go through all this DNS, ISP, LMNOP BS sounds pretty ridiculous just to be able to use a service that I have been using successfully for years until now.

I have had the problem for weeks now. Yesterday suddenly the problem disappeared without me changing anything. Time will tell if it stays fixed though.

Bottman, that is some excellent research you did there, and your hypothesis about the handover seems solid. It does make sense that they would want to collect usage data but not shoulder the entire burden of streaming the song.

Very odd that many ISPs are getting bad DNS entries for akamai.  I have FiOS and experience the issue, others on here have listed Rogers, so this is not limited to a single ISP.  Also odd that some DNS servers have the correct entries and others do not - just goes to show one of the ways in which the DNS system is flawed.

Thanks Racekarl.

ran flushdns got no result. This happened just a few weeks ago and was working fine, now I can't preview songs for longer than 6 or 12 seconds.- Help

Change your DNS server to 8.8.8.8.

For those of us who have no idea how to "Change your DNS server to 8.8.8.8" how about a step by step?

After I Googled how to do that and did it, IT WORKED!!!

I am having the same problem with this and tried the dns flush as was suggested and it didn't change a thing.