I've installed a Pi-Hole recently and 77% of queries are being blocked. Nearly all of them are from fls-na.amazon.com. I have no idea what that domain is. I've a heavy Amazon user and haven't yet noticed anything not working. Should I whitelist that domain?
Searching for fls-na.amazon.com
Found In EasyList-Lithuania. Matching Included:
fls-na-amazon.com
fls-na.amazon.com
Found In GandJ-Hosts. Matching Included:
fls-na-amazon.com
Found In KowabitBOD. Matching Included:
fls-na.amazon.com
Found In Mat1th-DNS-add-block. Matching Included:
fls-na-amazon.com
fls-na.amazon.com
Found In Michael-Trimms-Hosts. Matching Included:
fls-na.amazon.com
Found In Mother-of-All-ADBLOCKING. Matching Included:
fls-na.amazon.com
Found In Notracking-hostnames. Matching Included:
fls-na.amazon.com
Found In Steven-Blacks-Fakenews. Matching Included:
fls-na.amazon.com
Found In Steven-Blacks-Gambling. Matching Included:
fls-na.amazon.com
Found In Steven-Blacks-Porn. Matching Included:
fls-na.amazon.com
Found In Steven-Blacks-Unified-Hosts. Matching Included:
fls-na.amazon.com
I learned that fls-na.amazon.com is resulting from my installation of the Amazon Chrome extension. As soon as I remove the extension, no more requests for fls-na.amazon.com.
I believe this address fls-na.amazon.com, is used for authenticating apps "purchased" (paid or free) from the Amazon App store.
With it blocked the Plex Amazon App puts me in "Trial Mode", and is virtually unusable, but after whitelisting the address it validates my purchase just fine.
I would guess that it shows up in so many lists due to some Apps that use bad/malicious ads, but also authenticate purchases through the Amazon App store. Given that it's an Amazon domain, I'm pretty sure it's (mostly) safe from malware, and likely not the direct source of ads.
Other similar, and unblocked, Amazon addresses are: mas-ext.amazon.com mas-sdk.amazon.com mas-ssr.amazon.com
After some googling it seems the 'mas' is the "Mobile Associates API", where 'ext' is for in-app purchases (like Movies in Amazon Video), 'sdk' seems related to the API itself. The 'ssr' seems to be related to the App Store itself, but I'm not sure how.