WAN and Domain server Issue

[Xatruch]

Hello Everyone

I have an issue where a Mikrotik is the network administrator, I need to implement a pfsense to handle the network load, currently, the main employee network has a domain server with 192.168.89.5, static IP, and it CAN'T be changed, and many of the other services, connect using the 192.168.89.x or 90.x range, when I configure the pfsense, the WAN works fine, receiving from the mikrotik, but, when I setup LAN, I can't use 88.1 to 91.254 range, and I can't change any of the IP configurations on the rest of the network, since their POS, already works with that range.

any ideas here?

thank you

[NogBadTheBad]

https://forum.pfsense.org/index.php?topic=135620.msg742510#msg742510

Are you trying to introduce a firewall where there wasn't one before on your work subnet ?

[Xatruch]

Yes, that is what I am trying to do, there was no firewall before, but as I said, this is causing some trouble