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Your LimeSurvey version: Version 5.3.31 Own server or LimeSurvey hosting: Own server
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When activating a survey, I don't understand the difference between the Save IP address option, and the Anonymize IP address option.

If Save IP address is activated, the IP address is stored, and if Anonymize IP address is activated, the IP address is not recorded. It seems to me that this refers to the same option but in reverse formulation. Is it the case or is there a subtlety I missed ?

Thanks in advance.

Best,
Jessica Bourgin

 

Well,
there are four cases to investigate
1. IP = yes, anonymize IP = no
2. IP = yes, anonymize IP = yes
3. IP = no, anonymize IP = no
4. IP = no, anonymize IP = yes
Did you try to see the differences?

In case of 3. and 4. it is obvious that NO IP address is stored
1. Full IP address ist stored
 
2. The last group of the address is changed to "0"
 

Joffm
 

bourginj wrote:

When activating a survey, I don't understand the difference between the Save IP address option, and the Anonymize IP address option.
 

If you "anonymize" an IP in LimeSurvey, only parts of the IP address will be saved.

This should anonymize an IP address to a /24 subnet (IPv4) or a /64 subnet (IPv6)
For instance, the IPv4 address 192.168.178.123 is anonymized to 192.168.178.0.
The IPv6 address 2a03:2880:2110:df07:face:b00c:0:1 is anonymized to 2a03:2880:2110:0:0:0:0:0 (changing the last 5 blocks to 0)

  bugs.limesurvey.org/view.php?id=15997
 

Thanks a lot for your answers!

I must confess that for this one I did not try, since the description for the two options in the tooltips was very similar and I did not find the information in the documentation, I assumed I would get the same result.

Thanks for the explanation!

Best,
Jessica

I think this is another case for having just one setting with 3 options:
1. IP address saved
2. Shortened IP address saved
3. No IP address saved

These settings that influence one another and in some cases don't even make sense (cases 3 and 4 from Joffm - this should be one setting, because if you do not save the IP address there is no difference between those two).

Thanks. I had exactly the same question and this answers it.

In my opinion, the term 'anonymize IP' is misleading. There are still lots of information available just by masking the last octet of an IP address. You will be able to get at list the country where the IP address comes from by looking at the first 3 octets of an IP address.

The normal way to implement anonymisation is to use a 1-way hash function to hash the IP address. That way, you will not be able to recover the IP address. However, you have the benefit of being able to identify multiple responses from the same IP address.

Should be a feature request.

In my opinion, the term 'anonymize IP' is misleading.

Yeah, it is probably not the best term. But it actually is a degree of anonyization. Without the last 3 digits you won't be able to connect it to a specific IP/location, so there is a degree of anonymization. Similar to what webanalytics tools like Google Analytics or Matomo do.

So currently you have 3 options:

1. Do not record the IP (highest level of anonymity)
2. Record the IP but delete the last 3 digits (anonymous to the degree that you can't connect it directly with a person or a specific location, but can get some information via the different IP ranges)
3. Record the IP (non technical anonymity)

So you are proposing a 4th option. I personally don't really see the need, but feel free to make a feature request.

Here an example of how Matomo does it. They provide some more granularity than Limesurvey:
matomo.org/faq/general/how-does-ip-addre...ation%20function,0.0 .