mount a drive on different subnet

Hi Experts,

I like to mount a drive/folder from a different subnet and I wish to know how to accomplish this?

I have two subnets with 192.168.44.x and 192.168.56.x:
1. on 192.168.44.12 I have a share folder with path like this: 192.168.4.12/opt
2. I am currently on 192.168.56.15 and created a mount path like this: /mnt/rmote_opt

I've tried mount option with cifs like this:
mount -t cifs //192.168.44.12/opt /mnt/rmote_opt -o username=xxxxx,password=xxxxx but it doesn't work. Somehow I cannot find //192.168.44.12/opt.

Is there a way to change my current script or there is another way that allows me to mount a remote path from different subnet? Thanks