Re: Difference between ipp, ipps, http, https CUPS protocols?

[Anthony DeRobertis <anthony@derobert.net>]

Quick search of 
https://sources.debian.org/src/cups/2.3.0-7/backend/ipp.c/ shows there 
is no different between ipp and http, and no difference between ipps and 
https.

ipps and https force encryption, using SSL/TLS (just like you'd expect 
from https) (so if your printer doesn't offer encryption, say due to no 
certificates, it'll fail).

ipp and http do not require encryption (but may use it anyway, if 
available, via a TLS upgrade).

Probably CUPS offers both because some printers' documentation gives 
http:// URLs and some give ipp:// URLs.