Mandrake 9.x back around '02/'03
Apparently that was based on a 2.4 kernel - but back then it could have been a walnut for all I knew...
Setting up dial up was difficult enough, trying to get a USB DSL modem to work was eye watering...
I particularly remember the Mandrake GUI tools being extremely flakey. I didn't know about mailing lists or the few forums that existed back then (I'd only been using the net on metered dial up for less than a year (but computers for much longer - late '80s) so I just went out and bought a few books and struggled on - mostly breaking stuff and reinstalling.
Nowadays we have it easy (perhaps too easy). Forums like this one are a great, free, resource, populated by volunteers. It's a pity that some people don't really get this and often you see the type of member who turns up with an attitude where they feel it's ok to demand help and behave as if they are dealing with paid customer support people and thus believe they don't need to put in any effort for themselves.