Problem with DGM2 links to migrated programs

**Rich** · 07-10-05

(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.

#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.

Hopefully this will be enough detail to get a response.
Please don't PM me, post here.

**Fraser** · 07-10-05

Rich - thanks for looking into this and posting in such detail.

**consumerdeals** · 07-10-05

Just love the email i got today - I reported that forwarding links for 3 merchants are not forwarding correctly.

Rather than trying to fix the problem, here's what DGM Publisher and Integration Support had to say

> Please log into http://www.dgmpro.com/ to update you
> links for these programs.
> Contextual help is available to help guide you through
> the process.

I'm really unimpressed with this. I thought there was a commitment to maintaining the old links for a year...

**hpops** · 07-10-05

Excellent post Rich - thanks from all

**cyberbird1** · 07-10-05

Hi Rich,

Do you know what the likelyhood is of hitting this problem? Will these cookies typically contain more than 2Kb of data or is that only in rare cases?

**mark1966** · 07-10-05

Hello,

Thanks for starting this thread. I will be passing it along to our development team for a detailed response, but I can confirm that one of the key changes in our move from dgm2 to dgmPro was to move away from big cookies. We know they're a problem in dgm2, and dgmPro is designed to work just from a user ID, not reams of advertiser specific data.

We will get back to you. Apologies if this wasn't picked up before for a response, but I will make sure we give you some details early next week.

Regards,

**Rich** · 07-10-05

Originally Posted by cyberbird1

Do you know what the likelyhood is of hitting this problem? Will these cookies typically contain more than 2Kb of data or is that only in rare cases?

When I ran the test, between 1.6% and 4% of users had a problem. It was just a quick test, which I admit had some flaws in detecting unique users, and that is the reason for the broad range of figures. I could have done a more rigorous test, but that was enough to convince me that this was affecting normal visitors as well as publishers.

Thanks for looking into it Mark.

**EyeOfTheTiger** · 08-10-05

Originally Posted by mark1966

Hello,

I will be passing it along to our development team for a detailed response.

Regards,

Mark, am I correct in saying that in your signature you are the CHIEF TECHNICAL OFFICER? i.e. the head honcho for all things technical? Who do you have to pass it along too ? The junior techie guy who makes you a cup of tea in the morning ? Arent you meant to be the one at the top. Surely turning around to someone else i.e. the MD, FD, the receptionist they will say I dont know its your job to sort out and fix?

I think it is a nice and eloquent way of delegating responsibility or admitting that RICH seems to have nailed it on the head and now your stalling until YOU can think of a suitable answer other than admit that the seamless migration does in fact have lots of open seams which are rapidly pissing everyone's money onto the floor inlcuding ours, our fellow affiliate friends, your clients and ultimately yours.

We all want a fix to this nightmare so that we can do business with you.

I look forward to the resolution so that we can start to do business with you again.

I'm even half tempted to buy shares in dgm2 now they are stupidly cheap following the share price crash as a result of recent dgm business activities.

Surely they can only go up from where they are now. It cant get any worse can it ??? The question is when do I invest in shares. When will the share price go up ? When will you prove to the city and the rest of your investors, affiliates and me that you or anyone at dgm actually knows how to run the business in the best possible light.

I do not wish to be overly critical if at all. I am just looking forward to the day where I am able to do business with your clients. If you want my override, then you (DGM) need to facilitate this before someone else does.

Good luck with all the changes. I don't envy you one bit, and I for one appreciate open communication.

Keep me informed, keep me earning, keep me happy.

Mike

P.S. Rich - Awesome post, even for someone not techie like me I understood the problem and that there is A PROBLEM. Well researched and very well highlighted.

**drivetowin** · 08-10-05

I think to be fair to Mark he is DGMs CTO (and having had a few long discussions with him recently he certainly knows his stuff technically) but he may not have an indepth understanding of how every bit of their tracking works - thats the whole point of having a development team.

While DGM undoubtedly need to sort this out, I for one am happier with DGMs team approach which is not dependent upon the knowledge of just one person (unlike at least two of the UK networks where there is only one person at each with an in depth technical understanding of how their tracking works - God help all of us if that person gets run over by a bus!)

And to echo the comments of others, once again Rich, thanks for investigating this and reporting on it so clearly.

**EyeOfTheTiger** · 08-10-05

Having reread my post and Keiths comments I apolgise Mark, as it did seem as though I was firing away. Just needed someone to sound off at and you were top of the line. Good luck with getting this fixed with your team.

Mike

**cyberbird1** · 13-10-05

Mark,

Any news on that detailed response?

**mark1966** · 13-10-05

Hello,

I've collected all the information together now and will be writing it up later today.

Regards,

**mark1966** · 14-10-05

If your DGM2 links aren't working, this message will help you to resolve the problem. Our testing and stats demonstrate that DGM2 links do work with dgmPro, and that exceptions are limited to specific links with problematic parameters in them, and to 2 specific cookie problems.

Most of this information is already available elsewhere, but for your convenience I'm summarising it here.

Here's a checklist:

- Are you actually signed up to the program you're linking for? dgmPro doesn't refer traffic on for programs you're not approved for. You should check your subscriptions in dgmPro allow you to work witht he advertiser you're linking to.

- Do you have a problem with your DGM2 cookie? If you visit http://www.dgm2.com/diagnostic/cookietest.cfm you can get a dump of your DGM2 cookie content. If it says you don't appear to have a DGM2 cookie, your cookie is probably corrupt. This problem is an old and common one for DGM2 users, and you will need to delete your DGM2 cookie. dgmPro eliminates this problem permanently. The problem will predominantly affect publishers, who have accessed DGM2.COM frequently over long periods of time.

- Is IE6 truncating your cookie? We've modified our scripts so that the IE6 bug that truncates cookies we're passing between our systems won't cause problems any more. The fix is being rolled out and will be completely rolled out this week. The problem will predominantly affect users with large cookies: typically publishers.

- Is your banner ID valid? The I= parameter in DGM2 tags didn't have to refer to a valid banner ID in DGM2. If it isn't valid, dgmPro doesn't send you to the right destination. Did you create the link with a proper banner ID?

If none of these suggestions helps, you can replace your DGM2 link with a dgmPro link if you're short of time, or you can contact the publisher team who will help to resolve the problem with you.

Several people have asked until when DGM2 links will continue to be supported. We will continue to maintain DGM2.COM until the end of 2006 at the earliest, and we will announce ahead of time that we are withdrawing support for them.

Regards,

**Rich** · 14-10-05

To go through your points.

1) Why don't you show a error message, as other networks do in this situation, rather than just a 404 with no content? It seems silly to make people think your links are faulty when you could point them to the solution immediately.

2) Corrupt cookies is an old and common problem? How come its only just been admitted? What caused the cookie to be corrupt and why wasn't it fixed? What percentage of users of DGM2 links do you think have been affected by this problem over the years? (if a users cookie gets corrupted it seems likely that it would stay corrupt)

3) IE doesn't truncate the cookie, it's just you're trying to pass too much data between urls. What percentage of users of DGM2 links to migrated programs do you think have been affected by this problem over the past months?

4) Like in 1), if the banner ID is invalid wouldn't it be better to show an error rather than send the visitor to a blank page? Or even better, send the traffic on to the merchant and recorded it under a standard banner ID that means 'DGM banner ID unknown'. Surely your merchants would prefer to get the traffic and could cope with not knowing what banner was the source of some sales?

I will echo what Joe said in the other thread and say that it is good that there is a more communication from DGM now rather than the earlier "DGM head in sand syndrome".

**cyberbird1** · 16-10-05

Hi Mark,

There is no standard specifying maximum URL length so you cannot say IE has a bug truncating url's to 2Kb. Every novice programmer knows you don't use the GET method for passing large amounts of data.

The real issue here is not whether we affiliates have problems with dgm2 links but whether sales have been lost. At what point do these these cookies become corrupt or "too big"? After how many clicks on how many different links and in what time frame does the problem arise?