1. One significant change noted in summaries of "what was an eMac" report that the eMac used a PowerPC processor while all later stuff uses Intel. The flop between bigendian/littlendian data streams occured sometime around the switch, so connection to anything that assumes a different bit order than what you're connecting to could require a "thunker" that might be missing in your setup.

(thunking is a sort of generic term for describing swapping bit order or "cutting" back and forth between byte length packets. seldom encountered in the last decade or so since they've found simpler ways of doing it that don't merit bragging about it.)

2. For about the last year that eMacs were sold (and intermittently before that), sales were strictly limited to educational institutions, and it's possible that an "educational license" may have lapsed or been disabled and the eMac may not be able to boot past a startup (which might include finding a network, but not maintaining the connection).

(Random speculations from reading something somewhere, and with no significant knowledge of anything Apple, so don't take it seriously.)

John