topic dtCookie structure? in Open Q&A

dtCookie structure?

AntonioSousa — Thu, 23 May 2024 14:48:58 GMT

When diagnosing RUM problems, knowing the structure of dtCookie might come handy. In the documentation, we can see:
https://docs.dynatrace.com/docs/manage/data-privacy-and-security/data-privacy/cookies

Some are more intuitive than others.

In the following URL, @henk_stobbe shows that we have remove the 3A in app:
https://community.dynatrace.com/t5/Dynatrace-tips/how-to-reverse-engineer-a-dtCookie-so-you-can-see-what-placed/m-p/182943

But other keys are more cryptic, including srv & sn. And others I have found no reference, like rcs-3Acss

Anyone got more info on this that can be shared?

Re: dtCookie structure?

ChadTurner — Thu, 23 May 2024 18:48:06 GMT

the cryptic cookie structure.... I always cringe when i have to break it all down. let me see if one of my RUM contacts can break it down for us.

Re: dtCookie structure?

ChadTurner — Fri, 24 May 2024 11:07:29 GMT

@AntonioSousa the 'sn' and the values after it, is it possible that the string is the host ID or even the process/service ID that is supporting the call/injection?

Re: dtCookie structure?

AntonioSousa — Fri, 24 May 2024 12:19:45 GMT

@ChadTurner,

As a cookie, it wouldn't make much sense to be based on host & processes and even services. They all change quite frequently, while dtCookie seems to be pretty stable. It does support several applications though, so I suspect it keeps growing.

And then there's the length. The sn has 32 chars, while the host/processes & services have IDs with 16 chars. I have tried finding 16 char blocks, but with no success.

It would be more correct to match it to a User ID, but those are 45 chars long, although I suspect the first 13 digits are a timestamp. So, it's also 32 chars. I did a quick comparison with a session I know is mine, but they didn't match. Looking at the sn, it seems purely hexadecimal, while the User ID might be a Base64 encoding. Did a quick test, but it did not yield any conclusion...

Re: dtCookie structure?

ChadTurner — Fri, 24 May 2024 12:22:07 GMT

hmm, good job looking into those possible justifications. I reached out to a RUM person asking what all that means. Haven't heard back, ill hit up another rum expert that I have in my contacts.