New to Firewalls

[Roberth5]

I have a Network with internet access through a cable modem.  Running DHCP where my users are getting 10.1.xx.xxx addresses and I have a block of addresses reserved for some printers.

I have this opnsense system installed on a computer and can log onto it via 192.168.1.1 plugged into the LAN NIC and set-up my ether net card to a static IP address 1982.168.1.2.

So now do I just go plug this into my Cable modem (WAN) and my HUB (LAN) and it all works?  I have watched several youtube videos, and they make it sound like this system is good to go once installed and you set-up the time server and time zone.

I was wondering if this firewall became the DHCP server, if so is there a way to tell it that it should use 10.1.xx.xxx addresses?

Also it looks like I am supposed to somehow assign it the same IP address that is programmed into my cable modem as a gateway, how does that work?

I assume I need to turn off DHCP on my cable modem and assign it an address???

Over 10 opnsense youtube videos, and I am still in the dark regarding the above setup issues. 

Years ago I set-up my 1st firewall, it was "Untangle", that went pretty smoothly, this one seems much different.

Where can I go for some set-up tutorials that might get me to a point where I can put this on line in my system?

Thanks!

[yourfriendarmando]

If your cable modem router was issued to you from the internet provider itself,  you might need to put it in Basic Bridge mode. It will still have its own address of 10.1.10.1 . Once it is in this mode,  the routing and dhcp services in that modern will shut off. It will hand over firewall and routing to whatever connects to its port 1.

Opnsense I think normally sets up a basic subnet and dhcp server if you accept all the initial defaults. I would pick any other non routable subnet than 10.1.10.0 for your LAN. You can assign an address like 10.16.0.1/24 for your LAN interface.

The cable modem will connect your WAN and the cable service will assign your WAN a world IP address via DHCP.

Thoughts