Change the parent interface Vlan

[Heywhire]

I am new to this forum and have messed with pFsense off and on for awhile but nothing to the point of putting it into my network.

My setup now is configured to where I have my work devices outside the firewall and my personal stuff behind it. The HPC has plenty of ports to use and I wanted to put everything on the one switch. The problem I cannot get past is that my outside network is 192.168.4.1 and my inside has multiple subnets for the different boxes I test with (192.168.5.1, 172.16.5.1 and 10.0.5.1) but the outside is connected to a Netgear R6400 which supplies Vlan 1 (192.168.4.1) for internet but the parent interface for pFsense (192.168.5.1) also supplies Vlan 1. Both of these subnets will not work on 1 switch without the manipulation of vlans.

My setup right now is:

COX Modem–---->Netgear R6400-------->pFsense box----------->HP Switch. (The outside network is connected to the last 3 ports of the R6400)

What I would like to do is:

------------->pFsense----------------->HP Switch 192.168.5.1 Vlan1 (Inside Firewall devices)
                                        i
COX Modem------>R6400--i
                                        i
                                        ----------------------------------------->HP Switch 192.168.4.1 Vlan1 (Outside Firewall devices)

This way I can utilize the 1 switch for all the devices.

Or is there a way to pass 192.168.4.1 thru pFsense and bypassing all the functions? I would like to get rid of the R6400 and have the pFsense connected directly to the COX modem but the 192.168.4.1 subnet uses the R6400 for its DHCP.

If pFsense has to supply DHCP to the 192.168.4.1 network then it is subject to pFsense, right?

If this has already been asked and answered please point me in the direction where to find it.

Thanks

Joe