Problem with DNS server settings on Udoobunto

Discussion in 'Linux Ubuntu' started by chrisr, Jul 19, 2014.

  1. chrisr

    chrisr UDOOer

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    I am using the latest version 1.0 Udoobunto and have a BT (British telecom) broadband connection. No matter what I do in changing network settings, I can't connect to the internet and a web page, and keep getting the BT message "You're seeing this page because BT Parental Controls is active and you are attempting to connect to a DNS server outside of our network. You may have selected a different server in your network settings or installed an application that uses an alternative service"

    This applies to LAN and wireless connections. I have turned off BT Parental Controls, edited the IPv4 network settings (tried Automatic as well as tried manually configuring address, DNS server etc), but nothing seems to make any difference. Have tried pinging another computer on my network and that responds fine, but trying an external ping does not.

    All my other Computers (Including Raspberry Pi running Linux) work fine. What can I do to get connected?

    Many thanks for any advice!
     
  2. extream96

    extream96 New Member

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    Hi,
    You could do some test :
    If you try to connect udoo with the ethernet cable, it's works?

    What DNS server have you set ?
    If you have some free time, you can try to make a sd with android for understend if the problemi is linux or....
    Try and let my know!
     
  3. peter247

    peter247 New Member

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    If it`s not getting out of your router it`s not a dns problem it could be the default gateway address.

    DNS resolves a domain name into a ip address , but it`s the default gateway address which tell the route how to deal with a address which is not local (external) .
     
  4. extream96

    extream96 New Member

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    If internal ping works, the gateway ip is correct.
    If the other devices work, i think that there is an issue with udoo!
    I wait other test! :) :)
     
  5. peter247

    peter247 New Member

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    Sorry I may be confused what you are asking , BUT you are wrong with the statement below.



    First I will check we are on the same page .

    internal = any device on your local sub-net
    external = any device which is not on your local sub-net which need to be routed

    Are you using dhcp or static to configure your connection ?

    O.k back to your statement " If internal ping works, the gateway ip is correct." , if it`s a internal ping the default gateway is not used because it`s a internal ping , but that`s not to say the default gateway is correctly set up . Read about the default gateway and sub-net masks .

    Like I said before a internal ping does not use DNS at all , DNS is for resolving external address not local address which use a different method .
     
  6. extream96

    extream96 New Member

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    Sorry, but you are very wrong! I'm studying CISCO, the gateway is the name of the router's port which is connected the switch. The switch is connected to all the other devices. So you have created a lan for some devices. The router works at level 3 of the ISO/OSI model (IP), the switch at level 2(MAC ADDRESS). If you wont to comunicate with an other device in the lan, you send a PDU to the router, in the PDU there are: destination ip , source ip, source mac, router mac and other. if the destination ip matches with the subnet mask of the lan, the PDU is send to the device in the lan, if it doesn't match, the PDU is sends to the route that the router chooses or dropped if the router doesn't know the route. So the internal ping is constricted to use the gateway port of the router....
     
  7. peter247

    peter247 New Member

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    Yes , I took and passed the ccna too ( 2010 ) , plus the network + , msca etc etc etc.
    ( What can I say I was bored , now sick of all things Microsoft , so looking at linux exams )
    o.k so you are using a commercial grade cisco router and not a domestic netgear type etc router ?.
    Sorry , but a domestic router is normally just is a single port , 3 level router connected to a multiport level 2 switch , So most if not all your internal traffic will be level 2 switched.
    If you ping any device on your local sub net it is not the router part which is involved it will be the switch , as you say it is mac address to mac address using arp cache or wins .
    ( a switch being a level 2 device does not care about the ip address within the frame all it need is the source and destination mac address )
    If you ping out of the sub-net , eg 192.168.0.1 to 192.168.2.1 class c with a sub-mask of 255.255.255.0 , then it will need a method / interface to route , so it will give it the mac address of the router interface.
    Now the default gateway comes into play !!!!
    Read about routing tables
    But you are still wrong !!!! , you do not need are use dns for internal ping it is arp cache or wins , it`s netbios names
    you will be resolving not domain names OR need a workling default gateway.

    Ask you teacher about it , and remember Please Do Not Throw Sausage Pizza Away , ccna osi model joke
     
  8. extream96

    extream96 New Member

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    ok, sorry I'm tired and I'm confused .... I do not need to read it again, i know that for other devices in the lan is used the arp table , but i think that he have ping the router port and not other devices, however the dns ip is another setting, that in a normal lan is the same ip of the gateway, but he can try to change it with a google dns 8.8.8.8.
    In fact, in retrospect, if the external ping doesn't work, can be a issue with a gateway ip... we have to understand if he uses a dynamic or a static configuration!
     
  9. peter247

    peter247 New Member

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    Didn`t know about the 8.8.8.8 google nameserver server , so I guess that`s something new for me , I use the opendns nameservers at :- 208.67.222.222 and 208.67.220.220



    If you set the nameservers and default gateway to the router`s ip address you are saying use the router for the nameserver , then the router will get it`s nameserver from its ISP or static set.
    The default gateway should always be the routers ip address.



    if the external ping doesn't work , it is most likely the default gateway ( the default gateway is the gateway to the world ) , dynamic or a static configuration is just the method it is been set wrong.
     
  10. extream96

    extream96 New Member

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    It is a ip of the google dns, you can set other ip, the important is that it works.
    If he have a problem with a dns, a simple and quick test is change the dns ip.... However is more fast than ip of gateway because the gateway have to ask to the isp.
    He can do a ping to the gateway, if this response fine, the gateway ip is correct, other is this ip that is been set wrong.
    However he have tried both the configuration, but the issue is the same.
    i wait him for other response of the tests.
     
  11. peter247

    peter247 New Member

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    People can just get confused about how to set up a working network , because it can become quite a complex subject , and we really don`t have the information needed to know how he as configured the system.
    I`ve seen a lot of silly errors made by some clever people , but most of the errors are down to a lack of knowledge .

    Sound like he has found the solution by now , because he`s not come back to this topic for any replies.
     
  12. extream96

    extream96 New Member

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    it is true, people often make some error in the configuration of the network and this creates errors.
    We look forward to him response, otherwise I think he has solved!
     

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