sorry in advance for writing in english.
can you give more info on your problem if possible in english because google translate is very bad with your language.

If it's for working only on your local network :

router (open wrt) 192.168.1.1
nothing to do on your router for this config

computer 1 (ubuntu apache web server) 192.168.1.69 (static)
set one apache virtualhosts for the domain 123_test.com
add in /etc/hosts :
127.0.0.1 123_test.com
127.0.0.1 www.123_test.com

computer 2 (windows 7)
/Windows/System32/drivers/etc/hosts :
192.168.1.69 123_test.com
192.168.1.69 www.123_test.com

computer 3 (ubuntu 14.04)
/etc/hosts :
192.168.1.69 123_test.com
192.168.1.69 www.123_test.com

now on the 3 computers www.123_test.com = 192.168.1.69 and don't need a real domain or internet for that

if ssh is enable on 192.168.1.69 (web server) with ubuntu you can use nautilus, connect to a server, sftp://192.168.1.69 ;-)

I'm pretty sure it's not what you want to do but just in case if it can help.