Some internet problems - hopefully soon back

[Lago Mortis]

Hi!

I'm back from a 10 day holiday now. But I am not able to reach internet from my home computer at the moment.

Just before I left home, heading for the airport, I were doing some last checking on the net. Suddenly my computer went offline with a new ip adress I did not recognise (169.254.X.X).

A friend of mine helped me set up my net (main/game computer+ laptop) with a separate linux firewall. It has worked like a charm for 1 year, until last week. Yesterday I tried to dig into it. I hate when those things starts to make problems , I am a rather unexperienced net adm and my friend is unavailable at the moment. I found out that the internet works from my firewall, so the ISP/cable modem should be ok.

Today at work (many helpful people here), I found out that windows XP sometimes assigns 169.254.x.x adresses to computers as some default value, and that it could be a bit tricky to get rid off. But I got some methods to try. I'll see how it works out this evening.

Regards,
Lago Mortis

[Twisted Sister Jane]

Hi Lago,

welcome back!

I am not exactly sure of the IP numbering system, but 169.xxx.xxx.xxx could be a non-public address, one that is reserved for internal networks only. If that was the case, then you only could communicate with the outside world if your firewall had its own NAT system (translation of internal IP addresses to external ones) and I sort of doubt that this is the case.

I don't know the XP operating system so well since I still am using 2000, but it sounds like your computer might be assigning itself to an IP address instead of letting this occur dynamically, accepting the one from your internet provider.

For my Win2000 system, I can go into Control Panel -> Network and Dial up Connections and there I find an icon called "Local Area Connection" which basically handles the connection from my computer to the outside world via the computer's network card. If I right click on this I can choose properties to examine its settings. On the Win2000 system, I have several items that show up in a list box, and one of these is labelled Internet Protocol (TCP/IP). If I then select this and click on a button called "properties", I can see the settings that this Local Area Connection is using for this particular protocol. When I do this, I see on the main page only two options that could be set. The upper one has the choices "Obtain an IP address automatically" and this is the one that should be selected. This will cause your computer to seek what IP address to use from your internet provider, each time you turn your computer on and make a connection. Perhaps this is not selected?

The other option says "Obtain DNS server address automatically" and this should also be selected.

Your computer and internet is probably set up to be "online" automatically when you boot the computer up. If for some reason you boot up your computer and your internet is not currently working, then your computer will not be able to find an IP address to use. But if you use the automatic settings above, as soon as your internet connection comes alive (well, within a few seconds) your computer's network connection should recognize this and request a valid IP address.

If you really can't get things working, try to bypass your firewall briefly, just as a test, and see if your computer doesn't discover a valid IP address and can connect to the outside world. If it works without the firewall, but not with it, then there may be some settings in the firewall that are not correct. If the Linux firewall does not recognize your computer (or for that matter, your internet provider) as "valid" according to the rules set up in the firewall (which may be either as strict or unstrict as possible, depending on the way it was set up) then your computer will not be allowed to request a valid IP address from your internet provider; the request itself may be blocked by the over-ambitious firewall. This could possibly happen if you have some sort of strict rule somewhere that comes into conflict in a change from either your internet provider (they changed for example the IP address ranges they use) or your XP computer (ah, lovely Microsoft updates!). If your computer is not allowed to communicate with your internet provider and request a valid IP address, then XP will consider the computer to be offline, and perhaps automatically provide an internal IP address that doesn't work.

This is only a guess. It could be something completely different. In our case we have no firewall but only a router. Two computers are connected to this router. The router requests an externally valid IP address from the internet provider. When we turn our computers on, the router then assigns to each of our computers an internal IP address, something like 192.168.1.7.

Good luck! Hope you are online soon!

[Lago Mortis]

Thanks, Jane!

My guess is that my net is set up like this:

My cable modem is connected to my firewall (old linux pc with 2 network cards).
The linux pc gets an IP-adress from my ISP.
The firewall is connected to a small switch together with my 2 pc's.
The linux firewall assigns local static IP adresses for my 2 computers (192.168.0.x). The network control panel on XP's is set to obtain IP adress automatically. Those are the main lines of the setup that I actually have grasped
(Something similar to your router setup it seems to me).
Before last week my two computers (with their own software firewalls as well) could without problems access internet with this setup.

Then suddenly the windows pc's changed their IP adresses (to 169.X) and refuses to change it to something else. So far I have tried to unplugg network cable, restart pc, restart firewall, restart modem, disable/enable network inside XP, I even tried to go around the firewall and connect the pc directly to the modem. But so far the only ip adress that reappears is that dredded 169.154.x.x adress.

I googled on "169.154" and saw that more people seem to have similar problems. Seems like some sort of a bug-like windows-"feature", that locks the ip adress into a default range.

Regards,
Lago Mortis

[Twisted Sister Jane]

I've also just did a Google and found some site explaining how to set up a LAN on XP. And it shows as example specifying the options opposite to what I explained above in my post. The example used the other checkbox "Use the following IP address" which you do not want to do.

Or you can do this, but then you have to type into the IP address and subnet fields the correct values that apply to what your firewall is assigning.

Best to try is this:

Click Start and then select My Network Places. The My Network Places dialog box appears.

Click View Network Connection in the upper-left pane.

Right-click the Local Area Connection icon and select Properties. The Local Area Connection Properties dialog box appears.

Click Internet Protocol (TCP/IP) and click Properties.

See if the "Obtain an IP address automatically" is selected. Select it if it isn't.

Then see if "Obtain DNS server address automatically" is selected. Select it if it isn't.

To do this requires that you do have admin rights to your XP machine.

Hope this helps. It really sounds as if your XP box got its default setups changed somehow, perhaps during a Microsoft update to fix some potential weaknesses.

[Lago Mortis]

Thanks!
Now I have a couple of things to try this evening!


regards,
lago Mortis

[Twisted Sister Jane]

Well don't spend too much time getting it up and running! You need to be online tonite. There are warthogs in Tyria to feast on!

[darakus]

Hey Lago,

If the method Jane did describe doesn't work try attributing 192.168.0.X adresses manually

The method is similar to what was described by Jane:

Click Start and then select My Network Places. The My Network Places dialog box appears.

Click View Network Connection in the upper-left pane.

Right-click the Local Area Connection icon and select Properties. The Local Area Connection Properties dialog box appears.

Click Internet Protocol (TCP/IP) and click Properties.

Except that from there on you set up an IP adress manually :

IP : 192.168.0.X
Netmask : 255.255.255.0
Gateway : local adress of your Linux machine (most likely 192.168.0.1)

Validate.

Getting you address through the DHCP is easier but sometimes setting it manually is nice too.

Cheers,

Darakus

P.S. 168 adresses are adresses set by windows XP when he doesn't manage to get one from the DHCP.

[Radicc Tyranntt]

darakus said:

P.S. 168 adresses are adresses set by windows XP when he doesn't manage to get one from the DHCP.

If you look it probably says auto configuration address somewhere. Ip addresses in the 167-169 address range are assigned because you were not able to obtain an ip address and windows will hang forever if you don't get an ip from somewhere. So they setup a timeout where it auto configs to a junk address if you don't get one. So if you check your ip and it starts with one of those numbers you know you didn't get one.

and thats usually the problem with most people internet not working. Windows screwed up again! or norton/mcafee firewall, which is actually a windows registry problem so yeah, windows screwed up again.