I guess the obvious first question would be, did you try using a different ethernet cable?
Then there's: What does the ethernet port on the back of the Mac look like?
AAUI ports require adaptors to connect to a network using RJ45 cabling... the problem arrises in the fact that some of these adaptors come as two parts... a cable and the actual adapter... and for some weird reason use an RJ45 connector at the output end of the cable that plugs into the adaptor from the computer.. so you could conceivably have the cable, without the adaptor and not realize that you need the adaptor and not just the cable.
other then that... I have no other ideas.
By 'doesn't see', so you mean the status 'Local->Local Network', DHCP Clients Table (on the router's web configuration page) doesn't have an entry for it, or what ?
Maybe you should try not using DHCP on the Mac... You'll have to manualy configure your Mac's TCP/IP settings... I personally do not use DHCP on my computers, though I leave it running on my router for when I have friends hook up via wifi.
Under the WAN settings just find the DNS servers.
Then you enter that stuff into the Mac's TCP/IP settings.
Personally in my Mac IIfx I've got an Apple branded Nubus 10T AAUI ethernet card using an Asante AAUI to RJ45 transceiver adaptor connected to a Linksys 10/100 network switch using manual TCP/IP settings. So far it's been working pretty well.
If you're using network hubs rather than switches, maybe you should try just getting a 10/100 switch... switches are supposed to be smarter when it comes to handling network traffic than hubs. I know I had some very weird and annoying issues back when I first set up my network using hubs.
What OS are you using? You need OS 7.6.1 or something like that to have Open Transport installed by default (which does DHCP fine), or if you have OS 7.1 or newer you can download Open transport 1.x and the 1.2 upgrade from Apples website.
The Asante Mc3Nb is a very nice ethernet card (I hope you installed the drivers), easy to set up. 3com hubs/switches never bother my old mac networking gear even 10/100 varieties.
Yeah... what he said. Here's Apple's Legacy support pages.
Nope, you need drivers for the card, Open Transport (with updates) to get DHCP to work, and then you need to change networking from the built in serial port or built in AUI port (default) to the network card in the control panel section.