Well, first off what type of internet connection will you use?
If dail-up any standand external modem will do. The demo of
Miami 2.1 should work and get you online, it will work for
dail-up or broadband. TermitePPP is probably floating around
on ebay, but it is strictly dail-up. If you are wanting to
go broadband, a zorroII based ethernet card will be needed.
Search aminet for other possible software that supports 2.1.
One benefit of upgrading to OS3.9 is that it comes already
with a full working network stack, Genesis. 3.9 unfortunately
will more than likely require your kickstart roms to be
upgraded.
C Snyder