Configuring the Network Card

[uncleelvis]

I have a Knoppix Live CD. Last week I was giving it a try. I remember playing around with the network settings, and I eventually was able to go online and browse the Web. I wish I could remember what I did! Now, I can't get online. I use the "Configure Network Card" option and I said no to DHCP (as my ISP gives me a static IP address). I entered everything for IP Address, Subnet Mask, Default Gateway, Broadcast Address (I'm not sure what this is, but I entered the first three numbers of my IP address and used 255 as the fourth number -- per instructions found on the Net), and Name Server for Eth0.

It's driving me crazy! I really wish I could remember what I did last week. I do not have a router; I just use a DSL modem.

[Harry Kuhman]

..... I really wish I could remember what I did last week. I do not have a router; I just use a DSL modem.
This may surprise you, but we don't remember what you did either.

What DSL modem you have is rather important, as is your ISP. For specific help you should post this information. DSL typically uses PPPoE. Sometimes a router takes care of this for you. Some but not all DSL modems actually have a router built in that knows your account ID and password and does the PPPoE for you as well. I don't have such a modem, so I use a router. If your modem doesn't have a built-in router then you likely need to use the PPPoE software include with Knoppix, but see below before doing that.

I would absolutely never use a DSL internet connection without a router. The router provides a very important firewall protection that keeps hackers out of your system. The survival time of unprotected Windows system (http://isc.sans.org/survivaltime.html) has repeatedly been shown to be so low that they can't get the required security updates to protect themselves from known exploits before they are usually taken over by hackers (usually around 4-5 minutes!!!). Even with Linux and even with a Knoppix CD this is an issue. So I strongly urge you not to use that DSL system without a router. Routers are dirt cheap now and very very important. With a router (assuming that one is not in your model, which is likely correct or this would not even be an issue for you) you do all of the configuration in the router, including that static IP address, and then Windows, Knoppix, or any other system does all of it's configuration automagically by DHCP and you are on the network as soon as you are done booting.

[uncleelvis]

Thanks for the reply, Harry.

Actually, I'm glad I ran into this issue. I never considered exploring the router features of my DSL modem before because I have only one PC. I merely set it up per my ISP's instructions. Also, I assumed that this device's (Zhone 6381) firewall was always on by default. Actually, I'm still pretty sure it is. When I go to sites like grc.com, even with the Windows Firewall turned off, the results are that my ports can't be detected; that is, my PC is in "stealth mode."

Well, looking at this manual:

http://www.zhone.com/support/manuals/docs/63/6381-A2-GB23-10.pdf

... it seems I can configure DHCP after all. Up until now, I have been just using the static IP address my ISP assigned me plus the other usual addresses (Subnet Mask, Default Gateway, DNS Servers) in Windows' TCP/IP Properties. What was weird is that this seemed to work briefly under Linux, too. Anywho, I believe I can probably figure this out on my own from here on out. If not, I'll post back. Thanks, again.

[Harry Kuhman]

Yea, from the manual it's a DSL modem / router combo. The best way to use this is configure it so that the router is working and provides NAT firewall protection (this is extremely important for Windows users but handy for everyone). In your OS, Windows or Linux, you don't need or want to run any PPPoE software, just connect to the network by DHCP on the ethernet connection and get a local private IP address automatically. Knoppix will be on the network when it's done booting. Remove any PPPoE software that you installed in Windows for better performance and improved system stability (that may seem like an oxymoron with Windows but that PPPoE software can't help Windows, only make it even less stable). Configure the router to log into your DSL provider for you with your password and (if needed) to use your assigned static IP address (most DSL providers will still handshake with your router and provide the IP address even if it's a static IP address, but you didn't state your service provider and I likely wouldn't know their policy anyway (although someone else likely would), so do whatever you need to here as long as it lets you use the router and lets the router take care of the DSL connection).

I strongly suggest that you connect through the ethernet port only and ignore the USB connection on the Zhone 6381. Even if you decide later to add another computer, use the ethernet port only. To add additional computers, you should buy a small networking device called a "switch". A 5 port switch typically can be found for $20 or less (as low as free after rebate ). You do not want to add a second router, two levels of router and two layers of NAT will add complications and, when things work at all, slow the connection down. If you at some point decide to add wireless support, get a Wireless Access Point instead of a router or buy a Wireless Router that can be configured as a Wireless Access Point with the router section disabled (some can be configured this way but not all, see the manual for the device that you are considering to determine this capability).

When your router is working properly, it will assign your computer an address other than the static IP address that your ISP assigned to you. This is perfectly natural and correct. I looked through the manual quickly but didn't spot the exact address that will be used, but it is very likely in the 192.168.xxx.xxx range. The router then receives all packets and send the one intended for the Internet out with your static IP address in place of the local address. When packets come back to the router, it puts your private address back in the address field (along with some other changes) and forwards the packets on to the proper computer on the private network. Google "NAT" for more details if you want them.

[Harry Kuhman]

When I go to sites like grc.com, even with the Windows Firewall turned off, the results are that my ports can't be detected; that is, my PC is in "stealth mode."
Here's the real test: Look at Windows. Start a command prompt (shell). Type ipconfig . If the IP address that it reports for your etherenet connection (and I sure hope that you are using ethernet rather than USB) is the same as the public static address that your ISP assigned you, then you are not behind a NAT firewall. If the address that it assigned you is in a private range, most likely 192.168.xxx.xxx but a couple of other ranges are valid also including the 10.xxx.xxx.xxx range), then you are behind a NAT firewall. However, in this case Knoppix should work just fine and connect automagically by DHCP, so I rather suspect the former is true.

[uncleelvis]

Configure the router to log into your DSL provider for you with your password and (if needed) to use your assigned static IP address (most DSL providers will still handshake with your router and provide the IP address even if it's a static IP address, but you didn't state your service provider and I likely wouldn't know their policy anyway (although someone else likely would), so do whatever you need to here as long as it lets you use the router and lets the router take care of the DSL connection).

My ISP is Cavalier Telephone (aka Cavtel). I'll have to look at their site or perhaps chat with a support person to find out the policy. AFAIK, there is no password involved.

[uncleelvis]

When I go to sites like grc.com, even with the Windows Firewall turned off, the results are that my ports can't be detected; that is, my PC is in "stealth mode."
Here's the real test: Look at Windows. Start a command prompt (shell). Type ipconfig . If the IP address that it reports for your etherenet connection (and I sure hope that you are using ethernet rather than USB) is the same as the public static address that your ISP assigned you, then you are not behind a NAT firewall. If the address that it assigned you is in a private range, most likely 192.168.xxx.xxx but a couple of other ranges are valid also including the 10.xxx.xxx.xxx range), then you are behind a NAT firewall. However, in this case Knoppix should work just fine and connect automagically by DHCP, so I rather suspect the former is true.

I'm glad I found this forum! Thanks for all the info. I was mistaken. Without the Windows firewall, I'm not in stealth mode (even though the ports are still closed). But even with Windows firewall enabled, I can still be pinged. I trust that once I am done configuring the router properly, that will be fixed.

Yes, you were correct; ipconfig showed my static IP address.

[Harry Kuhman]

My ISP is Cavalier Telephone (aka Cavtel). I'll have to look at their site or perhaps chat with a support person to find out the policy. AFAIK, there is no password involved.
Wow, that's different for DSL. Still, I do believe that it would be best to either enable to router inside the modem and use it as a NAT firewall, or alternatively (although I don't expect that you'll want to do this, unless you add a wireless router) use a separate external router. Don't do both. In any case the router in use should take care of all PPPoE for you and you shouldn't need any special configuration on your system(s) at all, just DHCP with the router to get a private IP address and let it do NAT. Good luck.

Any Cavalier Telephone users who can join in on this conversation?

[Harry Kuhman]

I'm glad I found this forum! Thanks for all the info. I was mistaken. Without the Windows firewall, I'm not in stealth mode (even though the ports are still closed). But even with Windows firewall enabled, I can still be pinged. I trust that once I am done configuring the router properly, that will be fixed.

Yes, you were correct; ipconfig showed my static IP address.
Most routers have a setup option that allows you to enable or disable the router responding to a ping. I generally find it better to not disable the respond to a ping, sometime it's just handy to be able to have others ping you when trying to resolve a network issue. It's the router itself that responds to the ping (or not) on the public IP address, since there would be no way to decide which computer to send it to when many computers were behind the router. Even with ping disabled your local systems should still be able to ping each other (and the router), assuming that you have multiple systems and you don't have software firewalls blocking pings.

Some people do think that turning off ping helps them hide better, but understand that every packet that you send out to the Internet has that static IP address on it (or at least has someone's IP address on it and if you want a response it has to be yours). I could tell you your static IP address. Turn of ping if you want but don't depend on that for security. For that use a hardware firewall, and a NAT router will generally provide a simple but safe firewall for the average home user.

ipconfig confirms that you are not protected by NAT, the computer was directly reachable by the Internet. While having no open ports would seem like you should be safe, hackers are said to actually know a lot of ways around the lame Microsoft software firewall. A NAT router is much better defense. I also use a software firewall (although not the Microsoft one or ones packed with anti-virus software), but since unexpected packets never get to my system thanks to the NAT router, the software firewall is there to warn me when things try to get traffic out to the Internet unexpectedly. As such it's not perfect but still a lot better than nothing, but the real security comes from the NAT router.

[uncleelvis]

Hi, Harry. I'm posting from Linux Land. I have booted off the live Knoppix CD and I am using Konqueror. (For some weird reason, most of these words in the composing box are showing up red.)

I couldn't believe how easy it was. And since I used the "toram" command at bootup, the OS is running nice and fast.

There was no need to configure the network card (in the Linux environment, that is). Apparently, the DNS information is coming from the router.

But when I was in Windows (XP), I noticed that if I didn't manually enter the DNS info into TCP/IP Properties, regular Web addresses wouldn't work. However, numerical IP addresses would work. I later entered the Primary and Secondary DNS info and then all was fine. But I'm curious as to why the router isn't supplying this information like it is to Linux. Or perhaps it is sending the info, but something on the Windows end is conflicting.

(Hmmm, all the red text is gone. Strange hiccup!)

Well, thanks a million, Harry, for explaining routers to me. I'm thinking of eventually configuring a dual boot. I already have a Fedora CD (which I haven't used yet; it's not a live CD) and of course Knoppix. I understand Ubuntu is popular. Any recommendations for a Linux newb just starting out? Do you know of any decent online tutorials?

By the way, the NAT firewall is now working. Stealth mode all the way (and ipconfig confirms this)! :)

[Harry Kuhman]

There was no need to configure the network card (in the Linux environment, that is). Apparently, the DNS information is coming from the router.
Yup, part of DHCP. Or the router can tell the local computer to use the router's Ip address as a DNS server and with most routers they can take care of DNS (since they know where the DNS servers are and have to send on the packets anyway).


But when I was in Windows (XP), I noticed that if I didn't manually enter the DNS info into TCP/IP Properties, regular Web addresses wouldn't work. However, numerical IP addresses would work.
This isn't a Windows forum but, in XP, in the same box (Internet Protocol (TCP/IP) Properties) that you set the DNS addresses, there should be a radio button for obtain DNS server address automatically. Also be sure that you are not overriding this in the advanced tab. Other than that it should work, but if you have to set a DNS server then it's not all that hard.


Any recommendations for a Linux newb just starting out? Do you know of any decent online tutorials
Ubuntu is popular, But it's based on Debian and I would stick with Debian unless there were something in Ubuntu that you wanted that is missing in Debian (perhaps some new hardware driver, Debian can be a bit slower than some of the other distro in keeping up with the bleeding edge). But it's really a pick what's right for you kind of choice. Tons of Linux info on the Internet, most of it is even accurate. I don't have anything specific to recommend.


By the way, the NAT firewall is now working. Stealth mode all the way (and ipconfig confirms this)! :)
Yup, the router would have to be working if Knoppix connects automatically on a typical DSL connection (although many cable connections will DHCP with Knoppix even without a router). You'll find that this is a much safer way to run Windows, and will make all of your Linux network setup automatic.