Configure Cisco 2801, Juniper Firewall and DSL modem on same subnet

Unanswered Question


I'm trying to setup a new branch office with a DSL Modem, Firewall and MPLS connected to a cisco 2801. I have a /29 IP block from my dsl provider. Since the router is going to have one interface to the Modem and another to the firewall, is it possible to assign one IP to each and have rest available for servers behind the firewall? Or do i need to break the /29 into /30 netblocks?

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
thiru.vel10 Mon, 05/05/2008 - 19:19
User Badges:


2801 router is directly connected in DSL modem. In this router having two Fastethernet interface so you configure one public IP address in that interface and put one hub to connect the firewall and server. Local LAN is connect to Firewall LAN . I hope this is cleared your doubt

thiru.vel10 Wed, 05/07/2008 - 08:23
User Badges:

Configure the Public IP address in one Ethernet interface in Cisco router , and put one Hub that is connected to Ethernet interface for Cisco router, then now you connect the firewall and server in HUB and configured the Public IP address in server and Firewall WAN interface. For more information please see the PDF.

thiru.vel10 Thu, 05/08/2008 - 09:51
User Badges:

Hi I saw the Diagram which you attached. How many fastethernet interface you are having in Cisco router? You would connect the server and LAN switch in Firewall lan interface. Then all the traffic going through firewall. I think in firewall having port forwarding option so it very easy give the server access out.

Note: if you put Hub in between the cisco router and forewall means you can use all the public Ip address. For example if you want to connect the wireless access point , voice over IP phone, webserver etc.


This Discussion