If you are both on the same Network (LAN) behind a Router... forget it and wait for the Patch.
I´ve got the same issue and tried everything to solve this Problem.
Today i created a Ticket at Steam to get my refund for GRFS.
If you try to contact the UBI Support you`ll get only prewritten standard answers....
I had this If you can put your self in the DMZ on your router and get your friend to do it.
If you can make sure uplay and future soldier and run in admin mode.
Me and a few people play multiplayer and sometimes we have to close the game and uplay and then re open it all to get us to connect.
If you need help with the DMZ you will need access to your route password and you router model and i can find out how you put your pc in the dmz.
If you need to find your uplay .exe it is here C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher\uplay and for the game you need
C:\Program Files (x86)\Ubisoft\Tom Clancy's Ghost Recon Future Soldier and all you do is right click on them and go to compatibly and run as admin at the bottom
IF this doesn't help another thing i found helped with connecting to others was to get my friends to got to http://www.evenbalance.com/index.php?page=pbsetup.php and to get everyone to manually update punkbuster this helped us when it came to getting into online matches and removed an error from the top of 2 peoples screens