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Setup for Int->Modem>FirewallBox->Wireless Router. How, pls?

Last response: in Networking
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October 16, 2011 5:10:11 PM

Hi, All. I've been all over the web (including this sites 'Ultimate Guide....", but I can't find an answer to this question that addresses the issue at my level and/or incorporates all the devices. Be gentle with me. :) 

DETAILS:

I want to use an old PC as a dedicated box btwn a wired router (I guess it's just a switch, really?) and the wireless one that the household has access to, as follows:

ISP -> Wired Modem (need to buy) -> Old PC Linux based dedicated Firewall -> Motorola (Basic, from my ISP) Wireless Router

If it helps, I also have an unused Linksys Wireless (a couple of years old) that requires a separate cable modem.

QUESTIONS:
1) Are there particular specs/features that I need on any of these devices?

2) Is there a good guide to setting this up, or could someone give me instructions, please? (I know hardware and basic networking, but the DHCP level networking stuff alludes me.)

3) I am sure I want the dedicated firewall, but I am really lost on the Wireless box. Will it take data from the Linux Firewall? If so, do I need to mod the wireless router? The documentation is slim, and there seem to be much more limited info displays and setup choices than my old Linksys.
a c 79 F Wireless
October 16, 2011 5:31:35 PM

will the firewall be the DHCP server, too?

what is the model number of the wireless router?

do you create a separate network for the wireless network or use it just as an AP?

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October 16, 2011 6:10:12 PM

If DHCP is what I think it is (noob, remember. Winks), then I believe my current modem is doing that. I seem to recall there was an option to assign dedicated IPs. Does that sound right?

The Wireless Router is a Motorola Surfboard, Model #SBG6580. http://www.motorola.com/Consumers/US-EN/Consumer-Produc...

I am not sure about the last question. I am so lost on it I would not even know how to find out. Would you explain, please?

Thanks!
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a c 79 F Wireless
October 16, 2011 6:48:12 PM

The SBG6580 is a modem with a build-in wireless router which also has a firewall and DHCP.

does the "old PC Linux based dedicated Firewall" have two network cards?

which flower of Linux do you use?

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October 16, 2011 8:18:00 PM

Yes, that's the one. I think that there is another layer of security in a dedicated firewall, however. Also, the interface is very limited in terms of stats, reports and user control functions. For example I can't block ports for any one user or see any meaningful traffic info. Firewall software on a dedicated computer allows for much more flexibility.

The old PC only has one network card, but I was hoping to scrape up another one. If not I can find an old PC somewhere else.

The PC will be reformatted, loaded with some mainstream Linux distro (redhat or one of that family, but I'm not really worried about that), then have it just run firewall software. A nice lazy job in retirement.

So I'm still not clear on my Q's:
1) Are there particular specs/features that I need on any of these devices?

2) Is there a good guide to setting this up, or could someone give me instructions, please? (I know hardware and basic networking, but the DHCP level networking stuff alludes me.)

3) I am sure I want the dedicated firewall, but I am really lost on the Wireless box. Will it take data from the Linux Firewall? If so, do I need to mod the wireless router? The documentation is slim, and there seem to be much more limited info displays and setup choices than my old Linksys.

Thanks!
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a c 79 F Wireless
October 17, 2011 1:21:16 AM

I have a similar setup at my house.

I use a

Motorola 6120 cable modem

an old PC with two network cards (one for WAN and the other for LAN) and OpenBSD as the OS which acts as my pf firewall (Package Filtering) and DHCP server

a wireless router configured as a AP (Access Point)


to convert a router to a AP you can use the following steps:

connect the router to be converted only to a computer via network cable and log in

setup the wireless security

disable the DHCP and change the LAN IP to match the gateway IP but ending in .253

finally connect one of the four LAN ports of the AP to the main router, do NOT use the WAN port.

I never worked with that netgear before but there should be a way to disable the NAT, wireless, and firewall to have it work as a modem only.


there are great free firewall softwares like IPCop (using IPsec) or PfSense (using Package Filtering)

http://www.techradar.com/news/software/applications/7-o...
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October 25, 2011 8:48:29 PM

Thanks, Emerald, this is really helping me. (smiles)

I'm following most of what you say (smiles again). (Un)fortunately I am pathologically incapable of making assumptions (chuckles), so please bare with me. One thing I find helpful is to give each piece a clear name, so I don't confuse them. In this case I think of them as 1) The Motorola (the current dual purpose box), the Laptop (the one running the firewall software), and the wired box (the box that receives the raw data from the internet and passes it to the laptop). With that in mind, I have a few questions, please:

to convert a router to a AP you can use the following steps:

We are talking about the Motorola here, correct?

connect the router to be converted only to a computer via network cable and log in

OK, I read this as "reformat the laptop, install the firewall software, plug the Motorola into the laptop with a network cable and login to the Motorola. Then login to the Motorola through the laptop." Is that correct?

I can check with my IP provider on how to login that way. I have only ever logged in wirelessly. No problem, unless I have misunderstood you?

setup the wireless security

A bit lost here: This means config the software on the firewall laptop, correct? If so, are there any particular settings I need to look for or any suggested sites to read, pls? This is the part I'm nervous about getting wrong.

disable the DHCP and change the LAN IP to match the gateway IP but ending in .253

OK.. this means lobotomize the Motorola by using the laptop software to disable its DHCP function and assign it a dedicated IP xxx.xxx.xxx.253 , yes? I'm kinda shaky on subdomain issues: Will the three other octets be the same as the one my IP has assigned me?

I'm presuming the DHCP set up in the firewall software will be fairly simple (crosses fingers). I'm also supposing that we have set that software up on the laptop before beginning any of this conversion process. Wouldn't I have to if I want to assign the Motorola an IP at this step?

finally connect one of the four LAN ports of the AP to the main router, do NOT use the WAN port.

Sorry, which piece of hardware are we now calling the Access Point (AP), pls? If it's the Motorola, it has 4 cable connections spots: 3 are standard, and one is marked with a 1 over 2 tree icon. Which one is the WAN, pls?

This is beginning to be fun. Thanks! I look forward to hearing more.

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October 26, 2011 2:44:21 PM

Best answer selected by CharlieGirl.
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a c 79 F Wireless
October 26, 2011 2:48:36 PM

It will not be easy to use a laptop as a firewall since it has a wired and a wireless connection.

how are you planning to use the two of them? which one will be WAN and which will be LAN?
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a b F Wireless
October 27, 2011 12:08:11 AM

This topic has been closed by Area51reopened
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