I have a setup, where the single port 2600 router is in port 0/2 in the switch, outside network is on port 0/1, and the rest (0/3-0/24) should be clients for the second network that would be managed by the 2600 router.

I configured everything with two VLANs: 100 for outside (0/2-0/24), 200 for inside (0/1-0/2). 0/2 is a trunk port for the two VLANs.

The issue that came about is that I can't have two VLANs on at once: software doesn't allow it.

Now, I can ping the outside network devices (172.16.7.1, 172.16.7.103), and even google (8.8.8.8) from the router, but not the switch. Devices on connected get a DHCP lease properly but can't ping outside the network, just the router - 172.17.7.1 and the switch itself, 172.17.7.7.

The configuration for both the router and the switch are here, as well as below.

Router:

rt.throom#sho run
Building configuration...

Current configuration : 1015 bytes
!
version 12.1
no service single-slot-reload-enable
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname rt.throom
!
enable password To053cret
!
!
!
!
!
no ip subnet-zero
ip dhcp excluded-address 172.17.7.1 172.17.7.2
ip dhcp excluded-address 172.17.7.3 172.17.7.4
ip dhcp excluded-address 172.17.7.5
!
ip dhcp pool VLAN200
   network 172.17.7.0 255.255.255.0
   default-router 172.17.7.1
   dns-server 8.8.8.8
!
ip audit notify log
ip audit po max-events 100
!
!
!
!
!
!
!
interface Ethernet0/0
 no ip address
!
interface Ethernet0/0.100
 encapsulation dot1Q 100
 ip address 172.16.7.15 255.255.255.0
 ip nat outside
!
interface Ethernet0/0.200
 encapsulation dot1Q 200
 ip address 172.17.7.1 255.255.255.0
 ip nat inside
!
router eigrp 20
 network 172.16.0.0
 network 172.17.0.0
 no auto-summary
 no eigrp log-neighbor-changes
!
no ip classless
no ip http server
!
access-list 1 permit 172.17.7.0 0.0.0.255
!
!
line con 0
line aux 0
line vty 0 4
 login
!
end

Switch:

sw.throom#sho run
Building configuration...

Current configuration:
!
version 11.2
no service pad
no service udp-small-servers
no service tcp-small-servers
!
hostname sw.throom
!
enable password Oh5053cret
!
!
no spanning-tree vlan 100
no spanning-tree vlan 200
ip subnet-zero
!
!
interface VLAN1
 no ip address
 no ip route-cache
!
interface FastEthernet0/1
 switchport access vlan 100
 spanning-tree portfast
!
interface FastEthernet0/2
 switchport trunk encapsulation dot1q
 switchport mode trunk
!
interface FastEthernet0/3
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/4
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/5
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/6
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/7
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/8
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/9
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/10
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/11
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/12
 switchport access vlan 200
 spanning-tree portfast
!        
interface FastEthernet0/13
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/14
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/15
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/16
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/17
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/18
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/19
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/20
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/21
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/22
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/23
 switchport access vlan 200
 spanning-tree portfast
!
interface FastEthernet0/24
 switchport access vlan 200
 spanning-tree portfast
!
!
line con 0
 stopbits 1
line vty 0 4
 login
line vty 5 9
 login
!
end

sho ip route gives:

Gateway of last resort is 172.16.7.1 to network 0.0.0.0

172.17.0.0/24 is subnetted, 1 subnets
C       172.17.7.0 is directly connected, Ethernet0/0.200
172.16.0.0/24 is subnetted, 1 subnets
C       172.16.7.0 is directly connected, Ethernet0/0.100
S*   0.0.0.0/0 [1/0] via 172.16.7.1