Giving internet access to additional subnet on 877W

[andydenley]

Hi All,

So I bought some older Cisco kit and setup a basic network 192.168.100.0/24 (internal LAN). With .254 as the default gateway and this is also the 877W and this services my local network quite well.

I used a predefined config I got off the web and modified it to my needs.

Then I have built an additional network on subnet 172.16.0.0/20 for my test network of various Cisco routers/switches that I want to give internet access too.

I configured a VLAN 66 and assigned the IP of 172.16.5.1/30 on the 877 and assigned it to Fa3 on the other end I have a 1841 (Fa0/1) and assigned that IP 172.16.5.2/30.

Also on my 1841 (172.16.5.2/30) I setup a gateway of last resort of 172.16.5.1.

ip default-gateway 0.0.0.0 0.0.0.0 172.16.5.1

I can ping from 192.168.100.X network to the 172.16.X.X network and back again. and use SSH to connect to the test network (172.16.X.X) from the main LAN of 192.168.100.X

However when I try to ping outside of the network from 172.16.5.2 I get no response and my routing breaks.

On my BVI1 interface on my 877W I am using NAT (ip nat inside) should I need to use NAT on my new VLAN66 (172.16.X.X) and assign a access-list to get this working?

Or am I approaching this wrong, should I not declare the VLAN, but add this IP of 172.16.5.2/30 to BVI1 as a secondary and this would fix my issue?

Any help would be great. Config is attached...

Thanks,

Andy

[Karsten Iwen · Accepted solution]

You just need to allow your new VLAN to use NAT-services. Your ACL 1 which controls which IPs are NATed, already includes the new network.

interface Vlan66
 ip nat inside