NAT only one interface in Local lan

Hi to all,
I’m trying to do a NAT and I don’t know how to do.

This is the scenario:

** RB951 used as a PPPOE modem, on eth1:
with DCHP client and IP taken from ISP

/interface pppoe-client
add add-default-route=yes disabled=no interface=ether1 name=pppoe-out1 password=xxxxxxx user=blablabla


** bridge on eth2-eth3-eth4
without nat, in this network there is firewall and after firewall there is local network

** interface eth5 → here I want nat, and use this interface for guest network (with access points)

add address=ip.xxx.xyz.201/29 interface=bridge1 network=ip.xxx.xyz.200
add address=192.168.171.1/24 interface=ether5 network=192.168.171.0

Now is the problem:
I added dhcp server for eth5, I tried to add a nat rule:

/ip firewall nat
add action=masquerade chain=srcnat out-interface=pppoe-out1 src-address=192.168.171.0/24

It doesn’t work…

This is route table:

DST-ADDRESS PREF-SRC GATEWAY DISTANCE

0 ADS 0.0.0.0/0 81.174.0.21 0
1 ADC gh.xds.wdf.21/32 kl.yu.kh.fou pppoe-out1 0 <----> (taken from ISP dhcp)
2 ADC ip.xxx.xyz.200/29 ip.xxx.xyz.201 bridge1 0
3 DC 192.168.171.0/24 192.168.171.1 ether5 255


Can someone help me?
Many many thanks

Hi
Please follow the following procedure
/ip firewall nat
add action=masquerade chain=srcnat src-address=192.168.171.0/24

Thanks!
I’ll try on thursday