Help configuring a Cisco 1711 router


We have recently bought a Cisco 1711 router. Until now, I've been using a Linux based firewall. Our ISP provides us with a fixed DSL address and an extra range of six usable IP addresses (a .248 subnet) that are not contiguous to the DSL address, and are not routed through it. The DSL interface only gets 1 IP address. On the Linux firewall, I am using a setup that has all the .248 servers in a DMZ and I use proxyarp to bring this addresses forward so they appear to be on the same net as the DSL interface. Is it possible to create a similar configuration on the 1711, for example putting all the .248 servers in a vlan and using proxyarp to make this addresses appear to be on the WAN side of the router? While testing, I've noticed that as soon as I enable proxyarp I get "Duplicate IP address" message on the DMZ computer. Is there an alternate configuration that will allow access to this servers from the WAN side. All of this servers have legal IP addresses so there is no need for port forwarding or nat. Please answer to the newsgroup.

Thanks in advance.

Reply to
Leo Nardo
Loading thread data ...

I would like to help, but I'm not exactly sure of your setup. If, for example, your single IP address and /29 subnet both hang off the same router interface, I believe you should be able to add a secondar IP address on the 1711 interface. For example:

int fa0/0 ip address x.x.x.x secondary

As long as the ISP has a route pointing to that subnet giong through the single IP address and you have a default route back to your ISP, I think this setup should work. HTH.


Reply to

The setup is as follows:

".248" legal addresses subnet-> Vlan2 4-port WIC ->1711 DSL Private LAN -> Vlan1

Our ISP does not route the ".248" addresses through the the main DSL address (wich by the way is on a different subnet). I need to use proxy arp to bring the 248 addresses forward to the DSL interface. This is what I do with the Linux firewall. By the way, is it possible to have secondary addresses on the FastEthernet0 interface when using ADSL, When it is connected to an ADSL modem?

If I use the setup you are suggesting, I have to port forward from the DSL interface to the Vlan2 servers I guess.



Reply to
Leo Nardo Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.