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*nix Thread, Linux PCs can't lookup internal addresses in Technical; I'm having another exploratory foray into Ubuntu as a possible alternative to Windows for some of our workstations, as I'm ...
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    BatchFile's Avatar
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    Linux PCs can't lookup internal addresses

    I'm having another exploratory foray into Ubuntu as a possible alternative to Windows for some of our workstations, as I'm looking into the feasibility of buying out of our MS School agreement next summer.

    I installed Ubuntu a while ago and it looks like it could be a go-er. but one thing's puzzling me: I can't get ip addresses of internal servers to resolve.

    Anything outside the school works fine (i've put the LEA proxy in as the network proxy) and software centre etc is fine, ie I can ping bbc.co.uk but not cpsfilesrv1 (a server on the network).

    Edit: adding 10.105.* (covering our internal range) to the "ignored hosts" list in the network proxy bit has no effect - is there something else I should be putting in there?

    DNS seems to be working fine for Windows workstations, just not Ubuntu.

    Terminal Server Client won't connect with a server name, but will happily with an IP address. Oddly, "Places-Connect To Server" DOES work with server names

    DNS security allows "ANONYMOUS LOGIN" read access and It's a vanilla Windows 2003 Network (for now)...

    any suggestions where to look (at either end)?
    Last edited by BatchFile; 2nd December 2010 at 03:04 PM.

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    dhicks's Avatar
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    Quote Originally Posted by TonyRidal View Post
    I can't get ip addresses of internal servers to resolve.
    Is Ubuntu using the correct DNS server? How is the DNS server assigned, via DHCP or by static network settings?

    --
    David Hicks

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    tom_newton's Avatar
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    You should be putting your internal domains in the "do not proxy for" list. Otherwise the DNS lookup gets done on-proxy.

    Lets step back a bit from web browsers tho - they confuse matters.

    Try:
    Code:
    $ ping cpsfilesrv1
    $ cat /etc/resolv.conf

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    BatchFile (3rd December 2010)

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    BatchFile's Avatar
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    Quote Originally Posted by tom_newton View Post
    You should be putting your internal domains in the "do not proxy for" list. Otherwise the DNS lookup gets done on-proxy.

    Lets step back a bit from web browsers tho - they confuse matters.

    Try:
    Code:
    $ ping cpsfilesrv1
    $ cat /etc/resolv.conf
    that gives:
    Code:
    tony@tony-laptop-linux:~$ ping cpsfilesrv1
    ping: unknown host cpsfilesrv1
    tony@tony-laptop-linux:~$ cat /etc/resolv.conf
    # Generated by NetworkManager
    search cps
    nameserver 10.105.16.10
    nameserver 10.105.16.9
    nameserver 10.96.0.2
    # NOTE: the libc resolver may not support more than 3 nameservers.
    # The nameservers listed below may not be recognized.
    nameserver 10.64.0.2
    The "nameserver"s are correct - the first two are internal, the others at the LEA

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    Why do you have your LEA nameservers being directed at your clients? They should be set up as forwarders on your DNS servers only, that way your DNS servers handle all traffic.

    Ie:

    Client -> DNS Request -> Internal DNS Server -> DNS request -> LEA DNS Server -> DNS Request -> Top level DNS server

    etc...
    Last edited by localzuk; 2nd December 2010 at 03:40 PM.

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    BatchFile (2nd December 2010)

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    BatchFile's Avatar
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    Quote Originally Posted by jinnantonnix View Post
    Are you trying to resolve using the short name or fully qualified DNS name? If it works for FQDN but not for the short name, you could add the domain suffix in your network setup.
    I tried both, neither work

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    BatchFile's Avatar
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    Quote Originally Posted by localzuk View Post
    Why do you have your LEA nameservers being directed at your clients? They should be set up as forwarders on your DNS servers only, that way your DNS servers handle all traffic.
    Damn good question... I didn't set that bit up - and now you ask I can't think of a good reason!

    Edit: I've removed them manually, and now it works
    Last edited by BatchFile; 2nd December 2010 at 03:44 PM.

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    If you try doing an nslookup (ie. nslookup cpsfilesrv1) what is returned. Then, if you do an nslookup Google, what do you get?

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    BatchFile's Avatar
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    glad to report that with the settings localzuk suggested, it's working - I configured them manually initially, but now have corrected the DHCP options too. Cheers all! I'm sure I'll be back when I hit the next mystery

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