[zaarn]

The IP necessary for the connection itself is covered under necessary data, you can process it for the purpose of a request without needing consent at all. Same applies to shopping cart cookies or anything else that is essential to running a website and isn't being used for secondary purposes like data mining.

[mikekchar]

The key is to determine under which lawful basis you are processing that data. "Necessary data" is not a get out of jail free card. Because the analytics are not necessary to perform the contract (in any way that I can imagine), you can't claim contract lawful basis. Probably you are stuck with legitimate interest.

So I think you would have to notify the user that you are sending their IP address to the processor under legitimate interest and have a way for them to "object" to that use (i.e. turn off analytics). For legitimate interest, the objection can be after the fact, so having a configuration screen that stores a cookie that allows them to turn off analytics when they are on the site would probably do it.

[zaarn]

Since in my case, the processor is me, there is no data being sent elsewhere. I don't have a notification since all data collected is either heavily anonymized in client if possible or on the server side or simply not identifying. Since the data I collect is used to optimize the website experience, I think it's a good enough legitimate interest with no privacy impact.