open your VM right click your ubuntu distro choose settings and then choose network enable you your network adapter if it's not enabled by default in the "Attached to" options menu choose "Bridge adapter

type your modem's ip login go to local network(just a quick note that you have to figure out the settings on your or google it if your modem is not like mine/ mine is dlink dsl-2750u) scroll all the way down to dhcp reservation list click add enter your server's name the ip address you found by typing "ifconfig" and then the mac address for your VM

so you downloaded this linux debian based distro installed it in a VM(let's say oracleVM) set everything up you try to connect to it from your own computer (for example you try to ssh to the ip address) but you can't connect to it, you start troubleshooting and then you start giving up and just google it.to do that you'll need two things access to your actual modem and the VM settings and follw the instructions below:we are not done yet, boot to your ubuntu and login and type "ifconfig"you'll see your ip similar to your modems ip a bit let's say my modem's ip is '192.168.1.1' and the ubuntu server running the VM is '192.168.1.41'.Now we need to reserve the ip address so that it never changes except in one condition changing your modem.you should be good to go and do all your without any more headaches caused by these static ip addresses.