Non-invasive router migration

[Paketsalat]

Hi all,

I run pfSense as a firewall in production since 2012. It has WAN, LAN and VLAN interfaces and some NAT rules to internal servers.

• *  * THE CHALLENGE * * *

We have a Netgear router bypassing the pfSense firewall, which is going to be removed.

The plan is to first move the netgear router functions (DHCP etc) to pfSense.
As second step, I want to add a virtual IP with the IP of the Netgear box. This way, no client has to change its default gateway.

• • • THE QUESTION * * *

Is this a feasible approach?
How can I route (or rather "switch") all traffic from the LAN VIP (acting as default gw for clients) to the LAN interface?
NAT seems not really suitable here.

I invested ~2 days into research … maybe someone can give me a hint :-)

Thanks in advance!

[podilarius]

I think more information is required. Is the Netgear in the same subnet as the LAN on pfsense?
Yes, you can setup an IP Alias with the same IP as the netgear. If it is on a separate subnet, then you will only need to create FW rules to allow it and NAT rules so that traffic going out to the WAN is natted. Traffic between the 2 subnets should be automatic.
Personally, I would force default GW change, but this could be done for a slower transition. Those that are DHCP should transition over to the LAN IP by default.