Just as a test I did this

iptables -t nat -vnL
Chain PREROUTING (policy ACCEPT 504 packets, 62767 bytes)
pkts bytes target prot opt in out source destination
0 0 DNAT tcp -- ppp0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 to:192.168.2.150
1 52 DNAT tcp -- eth0 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 to:192.168.2.150
0 0 DNAT tcp -- eth1 * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 to:192.168.2.150

Chain POSTROUTING (policy ACCEPT 1 packets, 52 bytes)
pkts bytes target prot opt in out source destination

Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
then i tried to connect to http://192.168.2.154 which should have routed me to 192.168.2.150
but is did not work either