hello everyone
.first sorry for my english
i have simple configuration in my network
my diagram
2 ISP >>>> Mikrotik- Ether1(Wan1) Ether2(Wan2)>>>>>>Bridge-Local>>>>pppoe-clients customers
local ip pool for pppoe-clients 192.168.88.0/24
and i want route half of pppoe-clients to wan2 so i add this rule in mangle
/ip firewall mangle
add chain=prerouting src-address=192.168.88.1-192.168.88.122 action=mark-routing new-routing-mark=clients-to-wan2
and in route
/ip route
add dst-address=0.0.0.0/0 gateway=Wan2 routing-mark=clients-to-wan2
and everything its work
but after adding this rule in mangle the traffic between pppoe clients is blocked
example: client with address 192.168.88.10 cannot connect to or reach client with ip 192.168.88.150
when i disable mangle rule the clients can reach others again!!
how to solve this problem please?

Perhaps adding an addition parameter in mangle rule "dst-address=!192.168.88.0/24" should resolve the issue.

Perhaps adding an addition parameter in mangle rule "dst-address=!192.168.88.0/24" should resolve the issue.

very thanks bro skylark it's work like charm