(sorry if this posted ends up quite technical, but I want to be sure there is enough detail for DGM to reply to the point raised)
I have posted a number of times about a serious problem I see with how DGM are passing DGM2 cookies to the new S2D6 domain when a user uses an old DGM2 link to a program that has migrated to DGMpro, but so far they haven't commented on these issues. I would love to be proved to be wrong but so far it just seems to be being ignored.
The issue is with how they are passing two cookies from the DGM2 domain as GET parameters in a redirect to the S2D6 domain. This mainly affects users of Internet Explorer, but can also affect other browsers in more extreme conditions.
The problem is that both cookies can grow to around 5Kb in size but a GET request longer then 2Kb will fail in IE (
source). When this 2Kb limit is reached the request will fail, either with a error which, incorrectly, reports a DNS problem or nothing will happen - both problems that have been reported by others on the forum.
For other browsers the server will fail on requests longer than about 7Kb, so this limit could still be reached if both cookies are large.
Here is a very simple script that shows the 2Kb limit in IE. All it does is a meta refresh back to itself, once every second, adding 100 characters (' 123456789' * 10) onto the GET parameter each iteration.
PHP Code:
<html><head><meta http-equiv="refresh" content="1;url=get.php?data=<?=str_repeat(' 123456789',10).$_GET['data'];?>">
</head></html>
<body>
<p>GET size: <?=strlen($_GET['data']);?></p>
<p><?=$_GET['data'];?></p>
</body>
You can run this script
here (please only run in IE). You will see when it gets around 2Kb long it will stop.
As DGM also pass the cookie data between domains when showing a banner it can cause those to stop showing as well. Another simple test I ran, that tried to display a banner via a DGM2 link for a merchant that had migrated to DGMpro and which recorded if the image failed to load, showed that this issue is affecting normal users.
Some links:
http://www.a4uforum.co.uk/showthread...131#post180131 - This post was made when they first moved ediets over to S2D6, back in June.
http://www.a4uforum.co.uk/showthread...571#post190571 - This post lists three problems I see affecting DGM links, they replied to the thread just after but didn't respond to the specific points.
Later in that last thread are some posts highlighting the long term problems with the DGM2 cookie that I feel were ignored for years, this is why it really concerns me that they appear to be ignoring these issures with the DGM2 to S2D6 tracking.
Quote:
#176 KevinEdwards - I think the first point is an issue discussed in another thread that the new system aims to eradicate but was a potential problem for some publishers with dgm2.
#183 Me - Can you expand on what cookie/tracking issue/thread your referring to?
#185 KevinEdwards - The thread is the one below this one - about half way through.
#187 Me - Thanks Kevin. I guess it must be the issue with the DGM2 cookie getting corrupt/too big and stopping some links from working as its the only one which will be fixed when DGM2 cookies are no more. As far as I know this is the first time DGM have admited there is a problem connected to the cookie even though its been occuring for a long time and, as the cookie is triggering factor, surely has been affecting visitors as much as publishers.
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Hopefully this will be enough detail to get a response.
Please don't PM me, post here.
Problem with DGM2 links to migrated programs
