Good afternoon Andrew,

With an L24, I would suggest connecting via a USB cable and then changing its Ethernet address in RSLinx by right clicking on the L24 and selecting Module Configuration and Port Configuration.

If you were stuck in the filed without a USB cable, I would suggest the following:
1 – Disable your laptop's wifi
2 – Assign your laptop's wired Ethernet card a static Ethernet Address and Subnet Mask. If you are using VMware assign your virtual PC a static address on the same subnet as well.
3 – Open a command prompt and run IPConfig /all to see your PC's current mac addresses, ip address and mask
4 – Connect directly to the L24 via an Ethernet cable (i.e. no other devices on the same wired Ethernet network)
5 – Open the BOOTP tool and check the settings the mask set in the tool is the same you set for your pc
6 – Power on L24
7 – At this point only one MAC address should show up in the tool – after a few moments confirm only one MAC shows up, and then assign it the L24's ethernet address
8 – Open RSLinx and browse the RSWho to see if the L24 shows up now
9 – Access the L24's Properties and disable BootP

Hope this helps,

Shawn Tierney,
Instructor, The Automation Schoo