# [solved] Can't connect half of the web!

## keenblade

Very strangely, I can't open more than half of the internet like www.facebook.com with firefox, midori and arora. But opera and links browsers can open them all. There is no problem opening gentoo forums and google. How can it be? And the browsers outputs something like this:

```

Error - http://www.facebook.com/

The page 'http://www.facebook.com/' couldn't be loaded.

Cannot resolve hostname (www.facebook.com)

```

Also It is same with ftp. I can't reach some ftp sites that I know works fine. I am getting errors like this from filezilla:

```

Error:   Could not connect to server

Status:   Waiting to retry...

Status:   Resolving address of www.bla-bla.com

Status:   Connection attempt failed with "EAI_NONAME - Neither nodename nor servname provided, or not known".

Error:   Could not connect to server

```

There is nothing wrong with my isp, because my friend can connect with his vista laptop with no problem at my home.

----------

## nativemad

Hi, 

perhaps your internet connection only handles smaller packages. This is quite common on dsl connections...

You can try to set it lower like "ifconfig eth0 mtu=1492". If it works you can add a line like `mtu_eth0="1492"` to /etc/conf.d/net.

HTH, Cheers

----------

## keenblade

 *nativemad wrote:*   

> Hi, 
> 
> perhaps your internet connection only handles smaller packages. This is quite common on dsl connections...
> 
> You can try to set it lower like "ifconfig eth0 mtu=1492". If it works you can add a line like `mtu_eth0="1492"` to /etc/conf.d/net.
> ...

 

It was working just fine. So, I don't think it is a problem like you mentioned. But I noticed python is updated to 2.7.1 from 2.7.0. Can it be related to this? I am running python-updater now. And I connect with wireless. Also your command gives this with both eth0 and wlan0 :

```

LC_ALL=C ifconfig eth0 mtu=1492

mtu=1492: Unknown host

```

Edit:"ifconfig wlan0 mtu 1492" this does not error, but nothing changed. So I think problem is with my gentoo.

----------

## nativemad

ok!? strange!

Have you tried to use another dns Server? Or have you tried to resolve the names in the console (ping for example)?

Iptables isn't involved here or is it set up somehow on that machine? No proxy or similar?

I don't think it's a python update problem, as it works have the way...

edit:

sorry, it is without the = "ifconfig eth0 mtu 1492"

----------

## chiefbag

This looks like a DNS issue.

Are you connecting through a dsl router or behind a corporate or third party firewall?

Do you have another machine that you can verify the addresses you have tried are working from that machine?

Often some internet providers have been known to have experienced severe issues with there DNS servers at times, for example eircom.net

Check the output of the following 

cat /etc/resolv.conf

This should generally point to your routers ip ie. your default gateway.

post the output of the above and also the following.

route -n

You could also change the DNS servers on your dsl router to opendns which may prove more reliable then your internet provider should you find this to be a DNS issue. Also I would recommend checking boards to see if other customers who are with the same internet provider are experiencing similar issues.

Hope this points you in the right direction

----------

## keenblade

 *chiefbag wrote:*   

> This looks like a DNS issue.
> 
> Are you connecting through a dsl router or behind a corporate or third party firewall?
> 
> Do you have another machine that you can verify the addresses you have tried are working from that machine?
> ...

 

Ok, here it is:

```

cat /etc/resolv.conf 

# Generated by resolvconf

search homenetwork

nameserver 192.168.1.1

```

 *Quote:*   

> 
> 
> This should generally point to your routers ip ie. your default gateway.
> 
> post the output of the above and also the following.
> ...

 

```

route -n

Kernel IP routing table

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface

192.168.1.0     0.0.0.0         255.255.255.0   U     303    0        0 wlan0

127.0.0.0       127.0.0.1       255.0.0.0       UG    0      0        0 lo

0.0.0.0         192.168.1.1     0.0.0.0         UG    303    0        0 wlan0

```

 *Quote:*   

> 
> 
> You could also change the DNS servers on your dsl router to opendns which may prove more reliable then your internet provider should you find this to be a DNS issue. Also I would recommend checking boards to see if other customers who are with the same internet provider are experiencing similar issues.
> 
> Hope this points you in the right direction

 

Thank you very much. Opendns works great! It is sure a DNS isue. But I still don't understand why my vista installation on the same laptop and my friends vista laptop does work without opendns. So it is still something with my gentoo  :Sad: 

----------

## Veldrin

What provider are you using?

I recently found out, that my parents ISP (Bluewin/Swisscom) causes some weird DNS problem with Linux machines. As a quick fix, just I just added the google DNS servers.

cat /etc/resolv.conf.tail

```
nameserver 8.8.8.8

nameserver 8.8.4.4
```

Using /etc/resolv.conf.tail causes resolv to append its contents to /etc/resolv.conf automatically whenever that information is updated (e.g DHCP lease renewal)

V.

----------

## keenblade

 *Veldrin wrote:*   

> What provider are you using?
> 
> I recently found out, that my parents ISP (Bluewin/Swisscom) causes some weird DNS problem with Linux machines. As a quick fix, just I just added the google DNS servers.
> 
> cat /etc/resolv.conf.tail
> ...

 

Thanks. google DNS servers. with /etc/resolv.conf.tail works, too. So it must be related with my provider (Turk Telekom). Funny enough, the same provider works fine in my home city, but gives this problem in my work city. I'll mark this thread solved after I talk with my isp, again.

----------

## Hu

Since this appears to be a DNS issue and you are using a private range address as your DNS server, I suspect you are afflicted with a low quality home router or equivalent.  Some of these are known to have stupid on-board DNS servers that choke on some forms of query.  My guess is that the failing attempts request a AAAA record and confuse the device, whereas the successful queries request a A record and it works.  You can check this by using net-analyzer/tcpdump to inspect both successful and failed queries.

----------

## keenblade

 *Hu wrote:*   

> Since this appears to be a DNS issue and you are using a private range address as your DNS server, I suspect you are afflicted with a low quality home router or equivalent.  Some of these are known to have stupid on-board DNS servers that choke on some forms of query.  My guess is that the failing attempts request a AAAA record and confuse the device, whereas the successful queries request a A record and it works.  You can check this by using net-analyzer/tcpdump to inspect both successful and failed queries.

 

Thanks, I'll try net-analyzer/tcpdump. But It was working fine just 2 week before, so I don't think it is because of low quality device. Can this kind of problem happen suddenly because of low quality devices? For one year long there was no problem.

----------

## Hu

It is not something that will just change randomly, but depending on the device, it might have received an upgrade that caused it to believe it should provide AAAA service, without actually making that new functionality work.  It is also possible that some other change enabled your applications to begin issuing requests that they did not previously use.  What have you changed on each of those systems around the time that the behavior changed?

----------

## keenblade

 *Hu wrote:*   

> ...What have you changed on each of those systems around the time that the behavior changed?

 

Only important update is to python-2.6.x to 2.7.1. Anyway, there is no need to waste time for this, since opndns and google dns work.

Guys, thank you all for the help and time you've given.

----------

