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General Networking Question

First a little background.

I have two subnets at my office connected to the internet: (Mask - 2 Hosts (Mask - 30 Hosts is assigned to the external interface of my firewall. is my firewall's default gateway (My ISP's router). I do not have a router I control in front of my firewall.

The subnet is routed to my network by my isp. I have assigned to a NIC on my firewall so I can take the other addresses and use static NAT to servers I am providing services to (i.e. mail, ftp, etc). If I tracert from any device with a static nat it's first hop outside my network is on

Here is where the question comes in. I have a client that is bringing their own firewall over to put on the network since my existing one I cannot get VPN to work properly. My ISP doesn't have any IPs from the /27 setup on their routers as far as I know. My initial thought was to take an IP from my routed net to put on their firewall, for example The only device with a physical IP on this net is my firewall which I cannot use as the default gateway. So what would I configure on the client firewall for the gateway?

My thought was to call my ISP and see if the can assign to their internet connected router so I can use that as the default gateway. Is this the way to get this to work?



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Ok, I have the picture now.

In reply to: General Networking Question

You have the Netscreen on the network. It doesn't matter about subnets since you have all on the same network and no DHCP server.

That can create problems as the default gateway must be laid out as well.

-> I do see a problem in your basic IP assignments as you are not using private addressing inside your network?

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Private Addressing

In reply to: Ok, I have the picture now.

Definitely using private addressing internally, just wasn't sure about the public addressing since only my devices have IPs from the second subnet assigned.

I have 4 separate private networks behind my Checkpoint, and one of them is the one that we have been trying to get the VPN running for. So the idea was to stick another firewall and I will route the destinations that used to be going over the VPN on my Checkpoint to the new Netscreen firewall we will be installing. All actual private IP ranges internally, although I do have a client who insists on using public routable ips internally (that's another discussion all together) Happy

My internal networks are on VLANs and I do not have any workstations behind my firewall for those hosted networks, so even if I had to run DHCP I could with the way the VLANs are laid out.

I have been in situations where I had to do this same thing but instead of putting another static IP on it we would get a DSL/Cable line with static a static IP and bring it in that way, small less than 50 person networks. I typically put my gateways on .1 of the network (like and if I have to bring in another gateway I will put that at for example. As long as the routing is correct on the default gateway it works.

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That 40.x.x.x network...

In reply to: General Networking Question

*** UnKnown can't find Non-existent domain

I'd talk to your ISP about this. That's some unknown internet range and I can't find where anyone can use that range.

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Not the real IPs

In reply to: That 40.x.x.x network...

I didn't put the real IP addresses in, I substituted fake routable IPs for my question Happy

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I think you need to call Juniper, etc.

In reply to: Not the real IPs

Since I can't check the routing I'd call them and talk. I have an acquaintance there and from what he said they don't route your call to India. As it stands I'd get it all wrong as we can't talk about the IP plan.

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