CIFS share mount command hanging

I ran into an issue today when attempting to mount a samba share via cifs on a linux client where the mount command was taking two or three minutes to complete. Here's what the fix was in my situation, apparently cifs will first attempt to make a connection via port 445, in my iptables config I have that port dropped, eventually cifs falls back to port 139, however, if you specify port=139 in the mount options, it will go to the correct port the first time around and complete immediately.