I haven't touched this in a month and I forgot everything, I have no idea what happened.

Anyway, at school from home. We work with Mikrotiks in a VM, VirtualBox to be specific. What do I want? Connect a Linux VM through a Mikrotik VM to the Internet

eth1 is a bridge, eth2 goes into the Linux VM. IP addresses are set (static for now, no need for a DHCP server just yet), NAT is active, DHCP client got an IP from my home router and the implicit route is set correctly.

Mikrotik can ping the internet (IP addresses or domain names) just fine, the Linux VM can't even ping the outside IP address of the Mikrotik (the 192.168.0.75)

What am I forgetting? I know it is something very, very basic.

Help appreciated.

Show your firewall filter rules.

So the linux VM can successfully ping 192.168.1.1?

What has the address 192.168.1.5 - if it is the linux VM have you configured a default route?

So the linux VM can successfully ping 192.168.1.1?

What has the address 192.168.1.5 - if it is the linux VM have you configured a default route?

Yes, Linux VM can ping 192.168.1.1 (the "inside" IP address). 192.168.1.5 is a static address of the Linux VM.

Show your firewall filter rules.

Firewall Rules are empty. Is that wrong?

Am I missing a route back to the PC or something?

instead ping, you should do a tracert/traceroute from linux machine.

instead ping, you should do a tracert/traceroute from linux machine.

Doesn't even leave the machine

https://i.imgur.com/SQh2jip.png

When pinging from the router, see what the value of TTL is? Paste here the firewall rules too !

wrong/missing default gateway on the linux machine

wrong/missing default gateway on the linux machine

Alright, I have no idea why, but it works now. I posted the previous screenshot, turned off the VM, turned it on now and it works? I changed nothing, no idea why it works now. Anyway, thanks for help!

Paste here the firewall rules too !

I said before that Firewall Rules table was completely empty, in Firewall I only used NAT.

next time check display the route table because it's like the default gateway is not inserted.
route -n
netstat -rn
ip route list
and this should give us some info.

OR update your VirtualBox :)