Triple Wan - Dual DHCP, default routes

RouterOS Beginner Basics
1

Hey guys, so ive been on these forums for long time, just recently decided to register. Searched for what I could to get where I am now,

so here is my setup,

RB750
e1 - PPPOE #1
e2 - 3G Modem
e3 - PPPOE #2
e4 - DHCP LAN 1
e5 - DHCP LAN 2

–

PPPoE # 1 Primary WAN for DHCP LAN 1
3G Modem - Fallback for LAN 1

^^ This works, i can have them fall back and fail over and work no prob
What I want to stop, is DHCP 2 to be able to access the fallback 3G Modems Gateway on failover, to prevent that group of users from having net access.

Thats question 1.

Second question is,

PPPoE #2 is DHCP 2 primary wan, although I cannot get each of the PPPoE Connections to go to their own DHCP Nets

Goal here is to have
DCHP 1 - PPPoE 1
DHCP 1 - 3G MODEM
and
DHCP 2 - PPPoE 2


Anyways, if anyone could point me in the right direction, I would appreciate it. I guess I am looking at how can i define a gateway to each dhcp interfaces.

I think I am missing something in the NAT Rules. Anyways thanks for you time,
Cheers,

2

for 3G modem in firewall nat section you can put source nat only for DHCP1 LAN, so DHCP2 address will not get to the internet (it will but the internt would not work), or you can block them in firewall (better solution), src add=LAN_DHCP2 out. interface = 3g modem and also src add=LAN_DHCP2 out. interface = pppoe1

3

Ok thanks! Ill give that a shot