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Summary: NAT routers are a fundamental way to share an internet connection while protecting you at the same time. You may already have one. It's easy to check. I've seen you talk about NAT routers as firewalls, and so on. How do I know if I have one? The answer's not as obvious as a lot of people are thinking. Yes, much of the time a NAT router is an additional box ... a device that you plug your computer into that, in turn, plugs into your internet connection. And that box will typically say "router" on it. But that's not the only way you can end up behind a router. • As it turns out, many broadband modems also act as a router - and they won't say it on the outside. Knowing whether they're acting as a NAT router is important - you might be able to avoid buying an extra router you don't actually need, or you might be able to avoid installing firewall software you don't actually need. Finding out is fairly simple. My favorite way is to open a Command Prompt - that's usually done this way:
You'll probably get window similar to this one:
"...many broadband modems also act as a router
..."
In that Window type "ipconfig" followed by the enter key, and you should get something like this:
Now, like me, you may have more than one network adapter. The one you probably want to pay attention to is the one labeled Local Area Connection, for wired connections, or Wireless Network Connection if you're running via a WiFi or other wireless connection. The line you care about is this one: IP Address. . . . . . . . . . . . : 192.168.1.2 That's your computer's IP address. If it begins with "192.168", as mine does, then you are almost certainly behind a NAT router. IP addresses that begin with "192.168" are actually invalid on the internet as they are specifically intended for non-internet, local networks. The router performs what's called "Network Address Translation", or NAT, to translate from your local IP address to your internet IP address as assigned by your ISP. You may also see an IP address beginning with "10.", or some addresses beginning with "172." - these, too, may mean that you are behind a router of some sort, but these are typically NOT used by modems and consumer-grade routers. They're typically used for larger installations such as corporations, hotels or some ISPs. So if your computer is connected directly to your broadband modem, and you have a "192.168." address, then your modem is acting as a NAT router. If you have some other address, then it's not, and you probably want to investigate installing a NAT router or firewall. Related:
• Recent Comments
After reading a few different articles about using routers on your site (and at others), I am STILL confused. Like in your IP Config shown above, I seem to have 2 different IP addresses! I will explain... I have a cable modem and router connected to my desktop computer and use the router for wireless internet accesss on my laptop. After reading two of your articles on wireless access, I'm STILL not sure what's going on! My Netgear shows my IP address as beginning with 192.168, so from what you wrote, I am obviously behind a firewall. However....I have a Google addition on my homepage which also shows my IP address--and this address is totally different and changes every few days. (I believe they do this for security purposes). My problem is that when this address changes, I lose my internet connection on the laptop. Unplugging the router for 30 seconds and plugging it back does resolve the problem and my laptop is back online again. Why is this happening and can I resolve this problem without having to reboot the router every time this occurs? Every article I read is either too technical for laymen to understand or it doesn't address this particular problem or provide a fix for it (other than rebooting, which is what my ISP and another one of your articles said to do)! But I just can't believe there isn't a way to prevent this dropped connection from happening in the first place! I would truly appreciate your help because it's driving me crazy! Thank you, The only one that comes up for me is Local Area Connection 3. It has the 192.168 IP, so that means I'm behind an NAT Router. I checked by going to whatismyip.com, and it showed a different IP Address. Posted by: Steve at March 5, 2007 10:25 PMI have dialup and my ipconfig is showing that my ip address is 68.0. isnt that behind a nat router also?? i have dialup though with an internal old modem. i cant use p2p at all because i cant find the config web page to login to. Im pretty sure that i have to be behind a router. is this my isp's router or what? Posted by: Brandon at March 10, 2007 06:14 PMI need to know the config web login so i can port forward for p2p. I also went on my isp's webpage and there is a thing on there that says you have to pay$20 extra a month to have a static ip? Im used to dealing with cable n dsl but i just moved way out to the country and i have no other option. any help would be greatly appreciated. thanks Posted by: Brandon at March 10, 2007 06:18 PM-----BEGIN PGP SIGNED MESSAGE----- No, you're not behind a NAT router. It's important to note that EVERYONE is behind a router - routers are Your IP address is a "real" internet IP, so you're connected directly to Leo iD8DBQFF83SyCMEe9B/8oqERAhO0AJ0QKOcl8UQdtvAO/Bxijp3NmsKwzwCePme6 hi why my ip is 88.203.49.151? Posted by: arnold at April 17, 2007 08:43 AMHi, Leo, I read a question that was asked on the "behind a NAT router" page, but I did not see an answer to it. I have been working to resolve the same problem for months, hours and hours at a time. Can you please direct me to a help resource as I have not found an answer yet. After reading a few different articles about using routers on your site (and at others), I am STILL confused. Like in your IP Config shown above, I seem to have 2 different IP addresses! I will explain... I have a cable modem and router connected to my desktop computer and use the router for wireless internet accesss on my laptop. After reading two of your articles on wireless access, I'm STILL not sure what's going on! My Netgear shows my IP address as beginning with 192.168, so from what you wrote, I am obviously behind a firewall. However....I have a Google addition on my homepage which also shows my IP address--and this address is totally different and changes every few days. (I believe they do this for security purposes). My problem is that when this address changes, I lose my internet connection on the laptop. Unplugging the router for 30 seconds and plugging it back does resolve the problem and my laptop is back online again. Why is this happening and can I resolve this problem without having to reboot the router every time this occurs? Every article I read is either too technical for laymen to understand or it doesn't address this particular problem or provide a fix for it (other than rebooting, which is what my ISP and another one of your articles said to do)! But I just can't believe there isn't a way to prevent this dropped connection from happening in the first place! I would truly appreciate your help because it's driving me crazy! Thank you, -----BEGIN PGP SIGNED MESSAGE----- I don't have an answer for you. It sounds like your internet IP address is changing (that's The problem is that it shouldn't matter. Your router should I suppose you could try another router, but it's hard for me Sorry I don't have more for you. Leo
iD8DBQFHimUACMEe9B/8oqERAv5mAJ4tCEBuIaKxq2qORoA0Jq5oNt3ZywCfdP8M hello, i have a router siemens SL2-141. i did configure all the ports and stuff, but its a pain in my butt realy, nat makes the network 3 times slower ! i have a static ip adress configured, i have 2 pc's.
10.0.0.2 ip 10.0.0.138 gateway 255.0.0.0 netmask second (wireless) 10.0.0.1 ip 10.0.0.138 gateway (of course its same ^_^) 255.0.0.0 now i tried the option to remove nat, which blocks all ports. i did connect to internet, but i didnt actually was, but the router kept recieving, but i didnt recieve it.... i was constantly on my static ip that time, if you could help and tell me how to disable it and making the router work, even if i have to change the router gateway, i must turn it off ! its a pain in my behind O_O Posted by: ofir at June 20, 2008 10:31 PMPost a comment on "How do I know if I'm behind a NAT router?":
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