Since you didn't report any testing results you might try using ifconfig to 1) list your ethernet setup and 2) try to bring up your external NIC. Please pardon me if you already know the syntax!
Simply put, run ifconfig from a shell prompt to see what your NICs are doing, and pipe it through "more" to see a page at a time:
ifconfig | more
(On my keyboard the pipe is shift-backslash.)
To try to bring up your external interface:
ifconfig eth1 up
You can access a shell prompt by hitting ALT-F2 on the server's keyboard after it boots & shows you the admin screen, or by using an SSH-capable program such as PuTTY.