>Покажи вывод следующих команд:
>#sho ip int br
>#sho run int [каждый из интерфейсов]
>#sho ip route
>
>По текущим данным могу сказать следующее:
>1. На интерфейсе смотрящем в Сеть3 конфигурируешь ИП-адрес
>2. Пишешь аксес-лист который будет фильтровать трафик и устанавливаешь его на интерфейсы
>сетей.

#sh ip int br
Interface                  IP-Address      OK? Method Status Protocol                                                                                                                
FastEthernet0/0            10.1.0.15      YES NVRAM  up                    up                                                                                                  
FastEthernet0/1            X.X.X.X        YES NVRAM  up                    up                                                                                                  
FastEthernet0/1/0          unassigned      YES unset  down                  down                                                                                                
FastEthernet0/1/1          unassigned      YES unset  up                    down                                                                                                
FastEthernet0/1/2          unassigned      YES unset  up                    down                                                                                                
FastEthernet0/1/3          unassigned      YES unset  up                    down                                                                                                
Serial0/0/0                unassigned      YES NVRAM  administratively down down                                                                                                
Serial0/0/1                unassigned      YES NVRAM  administratively down down                                                                                                
Vlan1                      unassigned      YES NVRAM  up                    down                                                                                                
Vlan100                    192.168.1.1     YES manual up                    down                                                                                                
NVI0                       unassigned      YES unset  up                    up

#sh run int fa 0/0
Building configuration...

Current configuration : 272 bytes
!
interface FastEthernet0/0
description TO_LAN
ip address 169.254.0.1 255.255.255.240 secondary
ip address 10.1.0.15 255.255.252.0
ip access-group MAIN_FIREWALL_LOCAL in
ip accounting output-packets
ip nat inside
ip virtual-reassembly
duplex auto
speed auto
end

#sh run int fa 0/1
Building configuration...

Current configuration : 241 bytes
!
interface FastEthernet0/1
description TO_INET
ip address X.X.X.X 255.255.255.252 secondary
ip address Y.Y.Y.Y 255.255.255.0
ip access-group MAIN_FIREWALL in
ip nat outside
ip virtual-reassembly
duplex auto
speed auto
end

#sh run int vl100
Building configuration...

Current configuration : 103 bytes
!
interface Vlan100
ip address 192.168.1.1 255.255.255.0
ip nat inside
ip virtual-reassembly
end

#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is Z.Z.Z.Z to network 0.0.0.0

     X.0.0.0/30 is subnetted, 1 subnets
C       X.X.X.X is directly connected, FastEthernet0/1
     169.254.0.0/21 is subnetted, 1 subnets
C       169.254.0.0 is directly connected, FastEthernet0/0
     10.0.0.0/21 is subnetted, 1 subnets
C       10.1.0.0 is directly connected, FastEthernet0/0
C    Y.Y.Y.Y/24 is directly connected, FastEthernet0/1
S*   0.0.0.0/0 [1/0] via Z.Z.Z.Z, FastEthernet0/1

Ну в принципе я так и думал, просто на данный момент подключенная на vlan сетка не роутится в инет.