How can communicate two different subnets in same ethernet port

[garcia-g]

I was given two subnets by the ISP to access internet I have a 1720 router and i configure one subnet as primary and the other one like secondary in the Ethernet 0 interface. The pc´s now can access the internet but pc´s from different subnets dont see each other is there any way to route packets between different subnets in the same ethernet port?

[rfroom]

When you say the PCs cannot ping each other, do you mean they cannot ping each other, or just not Microsoft Browse each other??

[zahmed]

Make sure the PCs in primary subnet are using the ethernet's primary IP address as their default gateway while PCs in secondary subnet are using ethernet's secondary

ip address as their default gateway.

~Zulfi

[stefanb]

With several hosts on Ethernet residing on different networks you can add static routes with the metric 0 while pointing the gateway to the local interface. You have to do this for either side of any pair of hosts, which want to communicate. Router should be able to route between primary and secondary addresses on the same interface. If this does not work, try disabling ICMP redirects on that interface.