DOSBox *emulates* IPX. As far as DOS software running within it is concerned, it is IPX. but externally, it is actually tunneled through either TCP/IP or UDP/IP.
This is why your "real" DOS system doesn't see it, since DOSBox is not actually using IPX externally.
DOSBox doesn't support IPX natively. There are supposedly some forked builds that add "real" IPX, but I couldn't find any Active links to them.