Hello friends,

Currently Linux server is configured as router on the broadband connection.

Now there is a leased line. This is where your help is needed.

With the broadband connection, the cable from the ISP is connected to the router which is on the bridge mode and from it is connected to the firewall server(maqsquerading enabled).

Now With leased line, there is no router. How to tackle this issue?

Do I need the router and then connect it to the firewall server just as in previous case?
Or something else.

googled about this but nothing helpful came out.

Thanks is advance.

What type of connection are you provided with? Ethernet? Raw twisted pair?

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Thank you for reply.

The broadband is coaxial connection.It goes in to router/modem from ISP which has been set on bridged mode.
Routers output is then input to NAT-server.

The problem/doubt is, Now in order to connect through leased line
1) do i need router in between ISP and NAT server?
2) do I need switch, in which the ISP connection will input and from switch, one output cable will go to NAT server.
3) Or any other.

What is this NAT server? If it is behaving as a router, then no new router should be needed. This NAT server would be configured according to the ISP directions. It may be able to get that configuration from DHCP.

Between the NAT server and the ISP modem, no switch is needed unless you have a reason to connect something that bypasses the NAT server, or want to tap in and monitor what is going on (for diagnostic or forensic reasons). This assumes the NAT server is configured and operating in a way suitable to serve the rest of the network. I assume this is where all your translate, masquerade, and filtering rules will be.

Does the NAT server have 2 or more ethernet ports, or just 1?

you shouldn't need anything but you will need to know how the other side is configured (do you need pppoe or something like it, or you just put default route to their gateway on the other side)

Thank you, all of you for your comments and support.

The issue is solved.
The masquerading was needed to be done properly. And that did the trick.

Some observation may come handy for anyone:
1) while on broadband you "may" or may not need modem but on the leased line there is no need of the modem at all.


I set the iptable rules accordingly for the table nat and chain POSTROUTING and then for chain FORWARD.
There are few things which anyone should look for while settng those MASQUERADING rules.