Solution#1

• Three External Route Tables / Bounce Table Walking

• ip route add $ExtC via $RouterC table int1 proto static

• ip route add throw 0/0 table int1 proto static

• ip route add $ExtA via $RouterA table int2 proto static

• ip route add throw 0/0 table int2 proto static

• ip route add 0/0 via $Internet table main proto static

• ip rule add pref 15000 table int1 iif eth1

• ip rule add pref 15001 table int2 iif eth2

• ip rule add pref 15002 to $ExtC table int1

• ip rule add pref 15003 to $ExtA table int2

Notes: