Strange NTL / Networking issue

paulm17781

I'm looking for a little help with an odd issue I have come across.

I have NTL BB Max (well, 3mb should be 6). To my NTL modem is connected a linksys wrt54gp2. I have a laptop connected wirelessly and a desktop connected wired.

I was using my laptop earlier and realised I needed to send a mail from my desktop (different pop accounts). I turned on my desktop and could not connect to the internet. The laptop is working fine, I am using it now.

I investigated this a little more. From my desktop I can access my router admin page and I can access my cable modem admin page. I can not do anything else. I can ping each machine from the other but from my desktop I can not use the internet. It was working yesterday.

The only thing that changed since yesterday is I installed SuSe 10 on a new partition on the desktop. Both Suse and Windows are using the same IP (it is the same machine). I was only using Suse yesterday and it was fine (I didn't check it tonight) but Windows was working yesterday fine.

To reiterate. The desktop can see the network it is wired to. The desktop can see the modem outside the router. The desktop can not access the internet. The laptop does everything it should.

The laptop is definitely connected to my network (not a random wireless one). Any ideas???

Thanks

shltter

Try putting the NTL dns ips in your tcp/ip settings

of the top of my head 194.168.4.100


and 194.168.8.100

i think

keyran

Check the IP address both computers have. Make sure the Public IP address (the ntl one) hasn’t ended up on your laptop. Both computers should have IP addresses starting with 192.

paulm17781

shltter wrote:

of the top of my head 194.168.4.100 and 194.168.8.100

They are both there.

Keyran, I don't use 192.168 but my IPs are set in my tcp/ip settings. As I said, I can get to my router and NTL modem. Just not outside.

keyran

Have you tried pinging a URL or IP address. If you can ping an IP and not a URL might still be a DNS issue. Also try disableing Firewalls etc.

keyran

Have you tried pinging a URL or IP address. If you can ping an IP and not a URL might still be a DNS issue. Also try disabling Firewalls etc.

paulm17781

keyran wrote:

Have you tried pinging a URL or IP address. If you can ping an IP and not a URL might still be a DNS issue. Also try disabling Firewalls etc.

Yep, I can't get past my modem. Pings fail, I can ping the modem. E-mail doesn't work. Literally everything is fine until I try to get outside and that doesn't work at all!

Tippex

Did you check to see that you have the correct gateway on your pic i.e. the IP address of the ntl modem?

Post your IP details to give us a better idea

paulm17781

Tippex wrote:

Did you check to see that you have the correct gateway on your pic i.e. the IP address of the ntl modem?

Post your IP details to give us a better idea

I'm so not giving you my IP details.

My network is X. My default gateway (router) is X.1. Desktop is X.4 Laptop is X.2. NTL modem is 192.168.100.1 (not internal address).

irlrobins

Tippex meant your internal ip addresses. Harmless to give them out. Just don't give out your public ip address.

What do you have your gateway and primary dns set to on laptop and desktop?

paulm17781

It's not harmless to give out the IP address of a wireless network. It's unlikely to matter but I don't use non-standard for nothing.

The primary DNS and gateway on both match. Gateway is X.1 and primary DNS is NTL at 192.168.8.100

As I said, I can get passed the router, I just can't leave my place.

irlrobins

it pretty much is. If it ever comes to the case where someone gets to make use of ur internal addresses, well then you're already ****ed.

Anyway, can't be 100% sure since u won't give the full ip addresses, but I reckon you have the wrong gateway and dns settings. Gateway and DNS should both be set to the ip address of the router.

paulm17781

irlrobins wrote:

Anyway, can't be 100% sure since u won't give the full ip addresses, but I reckon you have the wrong gateway and dns settings. Gateway and DNS should both be set to the ip address of the router.

You do not need to know my full IP Address. I work with distributed systems everyday and understand IP issues. Trust me when I say my IP is X. This not the problem. I am certain of this. As I said, I can get passed the gateway to the modem. The gateway and DNS addresses are fine. If there was a problem with the gateway I would not be able to get to the modem. As I would not be able to get passed the router.

When I installed Linux I had problems with the gateway so when Windows would not work I checked this first. As I said, I can get to the modem. When I was having issues with Linux I could not.

paulm17781

irlrobins wrote:

it pretty much is. If it ever comes to the case where someone gets to make use of ur internal addresses, well then you're already ****ed.

Not on a wireless network. I have much security in place but I would rather not take the chance.

irlrobins

paulm17781 wrote:

I work with distributed systems everyday and understand IP issues. Trust me when I say my IP is X.

Righto. Just what sprung to my mind. Best of luck.

shltter

paulm17781 wrote:

It's not harmless to give out the IP address of a wireless network. It's unlikely to matter but I don't use non-standard for nothing.

The primary DNS and gateway on both match. Gateway is X.1 and primary DNS is NTL at 192.168.8.100

As I said, I can get passed the router, I just can't leave my place.

It is probably a typo but your DNS should be 194.168.8.100 not 192

liamo

My first thought is that it's a problem at the desktop because connectivity from the gateway to the Internet is fine, and that it's most likely to be either a problem with the DNS or Default Gateway settings. But you've discounted these.

However, you haven't said what error message you're getting back when you try to ping an Internet site. That might go some way to identifying the problem.

Additionally, you haven't said if nslookup works. This would confirm beyond doubt that your DNS setting is ok.

A tracert would also give additional information.

paulm17781 wrote:

I work with distributed systems everyday and understand IP issues.

Excellent. Then you'll be able to use Ethereal to sniff some packets from the desktop as you try to connect to an Internet site.

Instead of guessing what's happening, you'll be able to see what's happening. For example, is the desktop issuing a DNS request to the correct device (the router)? If so, is the Internet-bound http request (for example) addressed to the MAC address of the router?

Regards,

Liam

irlrobins

paulm17781 wrote:

As I said, I can get passed the gateway to the modem. The gateway and DNS addresses are fine. If there was a problem with the gateway I would not be able to get to the modem. As I would not be able to get passed the router.

Not strictly true. Had a fiddle with my own setup this evening and even with a blank or incorrect gateway and dns set, I could still access the router and its web admin page. I could not however access external sites. So having incorrect gateway could still be an issue here.

thund3rbird_

did you try connecting the desktop directly to the modem?

make sure to set tcp/ip to auto (ip & dns) & reboot the modem first

if it works this way then the problem is your own network.
if not then it's something on the machine itself

it's def not the modem - that's for sure.

when you are trying to ping past the router are you trying URLs or IPs?
you seem to have no problem with accessing IPs (modem / router / laptop) which looks like a DNS issue.

try ping ntl's dns - if that works then you are getting past the modem

then use nslookup to get an ip for any site
try ping the ip of the site - does it work?

another Q:
did you check the desktop tcp/ip against the laptop's?
make sure everything but the actual IP is the same

paulm17781

irlrobins wrote:

Not strictly true. Had a fiddle with my own setup this evening and even with a blank or incorrect gateway and dns set, I could still access the router and its web admin page. I could not however access external sites. So having incorrect gateway could still be an issue here.

No it is stictly true. I can get past my router. I just can't get passed my modem.

Shltter. I'll have to check that. I may have that wrong. Not certain off the top of my head.

Liamo, ping just fails. It's a common windows message but I can't remember it. I never thought of using Ethereal. I'll check that out later.

irlrobins

Is the modem in the same ip range as router?

paulm17781

irlrobins wrote:

Is the modem in the same ip range as router?

No. It is outside my network.

liamo

paulm17781 wrote:

Liamo, ping just fails. It's a common windows message but I can't remember it. I never thought of using Ethereal. I'll check that out later.

Ok.

Back to the subject of DNS and Gateway IP Addresses.... I know you've said that you're happy that the settings are not the issue here, however you'll have noticed that a lot of the posts here keep coming back to these settings. It would help to kill them off entirely as the problem if you would perform an nslookup and a tracert and report the results of these operations.

Regards,

Liam

paulm17781

I tried a traceroute and that just failed too. I suspect it is a DNS issue now, (194 vs 192) but I'd have to check that and I'm in work at the minute.

paulm17781

I got it fixed. It was the DNS set to 192 when it should have been 194. Thanks to whoever first spotted that.

Thanks to everyone who replied.