m0n0wall version 1.3 release, generic PC image.
DLink NICs, Realtek chipset, rl driver
Firefox 3.6 or IE8 from Windows, Firefox 3.5.x from Linux
See this thread for more background:
http://forum.m0n0.ch/index.php/topic,3732.0/topicseen.htmlSummary:
When logged in as username admin, clicking on Interfaces (assign) LAN | Secondary IPs tab, Secondary IPs can be configured.
When logged in as any other username (non admin) clicking on Interfaces (assign) LAN | Secondary IPs tab redirects to the System Information page, typically
http://192.168.1.1/index.php