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On Suse 9.2, I used yast to change from DHCP to a static IP, and as a result I lost my ability to resolve domain names on the internet. I ...
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  1. #1
    Linux Newbie
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    DNS without DHCP


    On Suse 9.2, I used yast to change from DHCP to a static IP, and as a result I lost my ability to resolve domain names on the internet. I managed to fix the problem by changing one of the name servers from some optonline ip to my router's gateway ip (192.168.0.1). I want to know why that worked.

    I'm assuming that DHCP used to take care of this aspect of networking for me, by supplying DNS servers in addition to my IP. But why couldn't I use my ISP's servers (167.206.3.141 and 167.206.3.140) directly? Wouldn't the router would just pass on DNS requests to those two anyway? My dad insists that the router blocked the outside server's attempts to communicate with my machine, but I was under the impression that since the connection was initiated by my computer, it wouldn't be an issue.

    I'm sort of a networking newbie, so I might be making a critical incorrect assumption somewhere.
    \"Nifty News Fifty: When news breaks, we give you the pieces.\" - Sluggy Freelance

  2. #2
    Linux Newbie
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    Your dad could be right. It is possible that your router is so stupid that even though you sent the UDP packet query, it blocked the UDP packet reply sent by your ISP's dns server. Or, it is slightly more likely that a stupid firewall local to the computer blocked the reply.

    We can test this easily enough. What do you see when you run these command:

    dig @167.206.3.141 www.google.com
    ping 64.233.161.104

  3. #3
    scm
    scm is offline
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    Have you defined your gateway as your router's IP address? That should be all you need to do. What does the route command tell you?

  4. #4
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    With the router listed as a DNS server (working):
    Code:
    dig 167.206.3.141 www.google.com
    
    ; <<>> DiG 9.2.4 <<>> 167.206.3.141 www.google.com
    ;; global options&#58;  printcmd
    ;; Got answer&#58;
    ;; ->>HEADER<<- opcode&#58; QUERY, status&#58; NXDOMAIN, id&#58; 33230
    ;; flags&#58; qr rd ra; QUERY&#58; 1, ANSWER&#58; 0, AUTHORITY&#58; 1, ADDITIONAL&#58; 0
    
    ;; QUESTION SECTION&#58;
    ;167.206.3.141.                 IN      A
    
    ;; AUTHORITY SECTION&#58;
    .                       5400    IN      SOA     A.ROOT-SERVERS.NET. NSTLD.VERISIGN-GRS.COM. 2005052900 1800 900 604800 86400
    
    ;; Query time&#58; 27 msec
    ;; SERVER&#58; 192.168.0.1#53&#40;192.168.0.1&#41;
    ;; WHEN&#58; Sun May 29 22&#58;06&#58;36 2005
    ;; MSG SIZE  rcvd&#58; 106
    
    ;; Got answer&#58;
    ;; ->>HEADER<<- opcode&#58; QUERY, status&#58; NOERROR, id&#58; 29061
    ;; flags&#58; qr rd ra; QUERY&#58; 1, ANSWER&#58; 4, AUTHORITY&#58; 4, ADDITIONAL&#58; 4
    
    ;; QUESTION SECTION&#58;
    ;www.google.com.                        IN      A
    
    ;; ANSWER SECTION&#58;
    www.google.com.         145     IN      CNAME   www.l.google.com.
    www.l.google.com.       149     IN      A       64.233.161.99
    www.l.google.com.       149     IN      A       64.233.161.104
    www.l.google.com.       149     IN      A       64.233.161.147
    
    ;; AUTHORITY SECTION&#58;
    l.google.com.           6449    IN      NS      c.l.google.com.
    l.google.com.           6449    IN      NS      e.l.google.com.
    l.google.com.           6449    IN      NS      a.l.google.com.
    l.google.com.           6449    IN      NS      b.l.google.com.
    
    ;; ADDITIONAL SECTION&#58;
    a.l.google.com.         13490   IN      A       216.239.53.9
    b.l.google.com.         13490   IN      A       64.233.179.9
    c.l.google.com.         13490   IN      A       64.233.161.9
    e.l.google.com.         13490   IN      A       66.102.11.9
    
    ;; Query time&#58; 16 msec
    ;; SERVER&#58; 192.168.0.1#53&#40;192.168.0.1&#41;
    ;; WHEN&#58; Sun May 29 22&#58;06&#58;36 2005
    ;; MSG SIZE  rcvd&#58; 228
    When I remove the 192.168.0.1 entry:
    Code:
    dig 167.206.3.141 www.google.com
    
    ; <<>> DiG 9.2.4 <<>> 167.206.3.141 www.google.com
    ;; global options&#58;  printcmd
    ;; Got answer&#58;
    ;; ->>HEADER<<- opcode&#58; QUERY, status&#58; NXDOMAIN, id&#58; 56479
    ;; flags&#58; qr rd ra; QUERY&#58; 1, ANSWER&#58; 0, AUTHORITY&#58; 1, ADDITIONAL&#58; 0
    
    ;; QUESTION SECTION&#58;
    ;167.206.3.141.                 IN      A
    
    ;; AUTHORITY SECTION&#58;
    .                       5235    IN      SOA     a.root-servers.net. nstld.verisign-grs.com. 2005052900 1800 900 604800 86400
    
    ;; Query time&#58; 22 msec
    ;; SERVER&#58; 167.206.3.140#53&#40;167.206.3.140&#41;
    ;; WHEN&#58; Sun May 29 22&#58;09&#58;21 2005
    ;; MSG SIZE  rcvd&#58; 106
    
    ;; Got answer&#58;
    ;; ->>HEADER<<- opcode&#58; QUERY, status&#58; NOERROR, id&#58; 15390
    ;; flags&#58; qr rd ra; QUERY&#58; 1, ANSWER&#58; 4, AUTHORITY&#58; 4, ADDITIONAL&#58; 1
    
    ;; QUESTION SECTION&#58;
    ;www.google.com.                        IN      A
    
    ;; ANSWER SECTION&#58;
    www.google.com.         343     IN      CNAME   www.l.google.com.
    www.l.google.com.       82      IN      A       64.233.161.99
    www.l.google.com.       82      IN      A       64.233.161.104
    www.l.google.com.       82      IN      A       64.233.161.147
    
    ;; AUTHORITY SECTION&#58;
    l.google.com.           7016    IN      NS      b.l.google.com.
    l.google.com.           7016    IN      NS      c.l.google.com.
    l.google.com.           7016    IN      NS      e.l.google.com.
    l.google.com.           7016    IN      NS      a.l.google.com.
    
    ;; ADDITIONAL SECTION&#58;
    b.l.google.com.         10132   IN      A       64.233.179.9
    
    ;; Query time&#58; 27 msec
    ;; SERVER&#58; 167.206.3.141#53&#40;167.206.3.141&#41;
    ;; WHEN&#58; Sun May 29 22&#58;09&#58;21 2005
    ;; MSG SIZE  rcvd&#58; 180
    In both cases the route table looks fine.
    Code:
    route
    
    192.168.0.0     *               255.255.255.0   U     0      0        0 wlan0
    link-local      *               255.255.0.0     U     0      0        0 wlan0
    loopback        *               255.0.0.0       U     0      0        0 lo
    default         192.168.0.1     0.0.0.0         UG    0      0        0 wlan0

    Grrr! Now it's working either way. I hate the way half the time I have to be very careful with my settings, and the other half I can bash random keyboard buttons and still have it work out just fine. Who knows if I'll be able to reproduce the problem now.
    \"Nifty News Fifty: When news breaks, we give you the pieces.\" - Sluggy Freelance

  5. #5
    Linux Newbie
    Join Date
    Mar 2005
    Posts
    230
    You kinda forgot the @ symbol in the digs. But I won't need to see 'em the right way if you got it working.

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