Sorta. The DHCP client table will show all clients that the router assigned an IP address. See:
However, it will not show anything if the client assigned itself a static IP address. It also won't distinguish between wired and wireless connections.
Much better is Airsnare:
However, that requires that you run a monitoring PC continuously.
Unfortunately, you have the WRT54GS v7, which uses an Atheros chipset, instead of Broadcom, and therefore does not support alternative firmware. If it was v4 or earlier, you could install DD-WRT firmware, and monitor the connection with SNMP, syslog, or one of the built in status web pages. For example, my home router at:
The built in logging feature of the WRT54G v7 stays in the router. Unlike other models that have syslog, this one requires that you login to the router and view the data locally. I don't have a v7 handy and can't tell you what it displays. The headings show "incoming IP address" and "port number", which does not include MAC addresses. Sorry.
Most such monitoring schemes require that the router support SNMP or syslog. For example:
Note the "send log to...." setting. That's a problem as the WRT54G v7 mutation does NOT have this feature. See settings at:
Other than sniffing the traffic between the WRT54G and the DSL or cable modem with AirSnare, I can't think of a way to do it with your current router.
The BEFxxx series was unique in that it would generate SNMP broadcasts with all kinds of useful info. I use Log Viewer 2.1:
for these devices. BEFSR11, BEFW11S4, BEFSR41, BEFSX41, BEFSR81, BEFVP41, WAG54G, WAG54G, Linksys/Vonage RT31P2. It produces some really nifty output. However, there's no alarm or trap sent for when someone new logs in. You can attach a script to the program, that will do that, but nothing built in.
My guess is perhaps less the 1 in a 1000 users of these products actually does any serious monitoring. The probably didn't include it because it used RAM, and RAM is allegedly expensive according to Linksys. As the product line progresses, the bottom of the line Linksys products arrive with less and less RAM, I guess to save cost. I don't approve of this, but that's what management apparently things.
I had to disable SNMP traps until I have hierarchical logfile storage setup; there were 35MB of traps from the BEF router in one month with very low wireless activity -- think of the volume in a busy setting :)