proxy server needs to point to two servers

[x7311]

Francis,
Thanks for the great help.

Here is the update nginx configuration.
http://pastebin.com/736sxcmK

The public domain is actually an ip-address of the server. Let's called
it 999.99.99.99

Since they are behind private firewall, for me to access this (at this
stage), I have to SSH tunnel into the master server 999.99.99.99. In any
case, I ping dev.999.99.99.99 on the master server and it said unknown
services.

So I edited my 
http://pastebin.com/VME5c4Dw

I can now ping dev.999.99.99.99 but I think this is so laughable... it
seems like I don't really know what I am doing :(

me at my_PC:~$ ssh studentXYZ at student.college.edu -L 1234:dev.999.99.99:80
-N
studentXYZ at student.college.edu's password: 
channel 2: open failed: administratively prohibited: open failed
channel 2: open failed: administratively prohibited: open failed
channel 2: open failed: administratively prohibited: open failed
channel 2: open failed: administratively prohibited: open failed
channel 2: open failed: administratively prohibited: open failed

It seems like I didn't have it right...
Thanks for all the help so far.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,228113,228118#msg-228118