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Support for cPanel is void due to unsupported modifcations (/etc/resolv.conf)

Discussion in 'General Discussion' started by chrisbond, Jul 29, 2003.

  1. chrisbond

    chrisbond Well-Known Member

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    Every time /scripts/upcp is ran you get a message at the top saying:

    Support for cPanel is void due to unsupported modifcations (/etc/resolv.conf)

    My /etc/resolv.conf contains:

    domain mydomainname.co.uk
    search mydomainname.co.uk
    nameserver 127.0.0.1
    nameserver 66.197.217.12
    nameserver 66.197.217.11
    nameserver 66.96.193.2
    nameserver 66.96.194.2

    Why is this not support and if so what should it contain?

    cPanel.net Support Ticket Number: 19547
     
  2. ciphervendor

    ciphervendor Well-Known Member

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    You should only have 3 nameserver lines; the last two won't ever be used.

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  3. Crazy Pete

    Crazy Pete Well-Known Member

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    Same here

    I got that message starting today, but my /etc/resolv.conf only contains...

    domain expectedmiracles.com
    search expectedmiracles.com
    nameserver 127.0.0.1
    nameserver 209.123.167.10
    nameserver 209.123.159.1

    What's going on?

    cPanel.net Support Ticket Number:
     
  4. chrisbond

    chrisbond Well-Known Member

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    The fix is simple (this was from cpanel support ticket)

    chattr -i /etc/resolv.conf
    chattr -i /etc/hosts

    Basically the sticky bit stops cpanel having access to these files.

    cPanel.net Support Ticket Number:
     
  5. Crazy Pete

    Crazy Pete Well-Known Member

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    Ohhh that's right, I had changed that. :) Thanks, I forgot I even made that a +i until you said that.

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  6. shaun

    shaun Well-Known Member

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    dont use 127.0.0.1 in your resolv.conf use the base ip of the server.

    cPanel.net Support Ticket Number:
     
  7. Crazy Pete

    Crazy Pete Well-Known Member

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    Why is that, Shaun? I thought by not having the localhost IP in there it would take longer to do DNS lookups for local sites. Am I wrong?

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  8. Website Rob

    Website Rob Well-Known Member

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    You'll note that:

    /etc/resolv.conf
    /etc/hosts

    are basically the same -- or should be as far as IP addresses go.

    "resolv.conf" only needs two IPs: 127.0.0.1 & base IP for the server.

    "hosts" should show the same two IPs, just state them a bit differently.


    Maybe Shaun could go into a bit more detail as to why the localhost IP is not needed in the "resolv.conf" file? And here I thought, I was doing good to get it down to two lines. Now a suggestion comes along to have only one line.

    cPanel.net Support Ticket Number:
     
  9. jamesbond

    jamesbond Well-Known Member

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    I think it doesn't make sense to use 127.0.0.1 and base IP (if you use that ip for nameserver also), you should use one or the other.
    And more importantly you should add 1 extra nameserver which is not located on the server just in case BIND is down on that server.
     
    #9 jamesbond, Aug 2, 2003
    Last edited: Aug 2, 2003
  10. shaun

    shaun Well-Known Member

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    When i first started to learn dns years ago all docs always said never to use 127.0.0.1. I know 127.0.0.1 works but i always used the base ip and never new why it mattered.

    The original reason i think all the docs said this was because their was a bug in bind that caused problems with localhost lookups. With in the last cupple months i figured out what the diffrence is between 127.0.0.1 and the baseip.

    When using 127.0.0.1 bind acts as a cacheing server. It will return information that it has cached if it has that information. So for example, a reseller thinks it would be funny to add yahoo.com. Now that a bind zone exits for yahoo.com when using 127.0.0.1 in your resolv.conf it will report back to you the information in that zone (which would be wrong). But if you where to have the base ip of the server listed in the resolv.conf now the server would see that it's not authortive for this domain, query the correct server, and report the correct information.

    Now i know that if somebody where to add yahoo.com the server would still have issues because of the fact that yahoo.com would now be in localdomains and the mailserver would think it's local. Since we use external nameservers it's vital that our server actually go out and make the query.

    The only problem i've ever had with using 127.0.0.1 is when somebody was using a script i wrote called ckcpaccts (http://www.cplicensing.net/extras/scripts.php) basically the script resolves the domains on the server and checks if they point to the correct ip, if the dont, it lets you know. if you where to use 127.0.0.1 the script would report wrong.


    hope you guys can understand this, was kind of written quickly.

    cPanel.net Support Ticket Number:
     
  11. jamesbond

    jamesbond Well-Known Member

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    I'm trying to follow you...a few questions...

    Why would you use the base ip address if no nameserver is connected to that ip?

    In your case you say you use external nameservers, there is then no point of putting the base ip address/local nameservers in etc/resolv.conf at all, is there?

    If one is using local nameservers though then I don't see what the difference is between using 127.0.0.1 or your local primary nameserver ip (regarding your yahoo example)

    I thought people who use local nameservers should put the local nameserver first (faster queries) and add the external nameservers after that in case the local nameserver is down.

    A while ago I did find some references regarding a problem that might occur when using 127.0.0.1 instead of primary nameserver ip, but these were all old documents. I doubt the problem still exists in BIND 9 (or 8).

    cPanel.net Support Ticket Number:
     
  12. shaun

    shaun Well-Known Member

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    We use external nameservers yes, but we use the local named process as one of the resolvers.

    Remember theirs 2 parts to bind, the resolver and the authoritive server.

    maybe i didnt make my self clean in the example above, but if you add a zone called yahoo.com pointing to ip 1.1.1.1 and then do nslookup (assuming the first nameserver entry in your resolv.conf is 127.0.0.1) the server will return the address of 1.1.1.1 for yahoo.com. But if you where to use your base ip in the resolv.conf the nslookup would inturn query the local resolver which would realize it's not authoritive for the domain yahoo.com and would then query the correct server and return the correct ip.

    I dont know about all of you but i'd rather have accurate data.

    cPanel.net Support Ticket Number:
     
  13. jamesbond

    jamesbond Well-Known Member

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    Ok now I understand! :)

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  14. LS_Drew

    LS_Drew Well-Known Member

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    I think it would be nice, especially since Cpanel has recently decided to make some policy changes in this area, if Nick himself, or a Cpanel staffer, would give us an exact, LINE BY LINE example of the way Cpanel expects resolv.conf to be.

    There are far too many theories and ideas that get kicked around the board here. We need a definitive answer from the horse's mouth.

    cPanel.net Support Ticket Number:
     
  15. shaun

    shaun Well-Known Member

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    WHM will actually tell you to use 127.0.0.1. I've submited to nick asking him to change this.

    it's simple, you can have 3 nameservers listed, and if you want you can have a search and domian in there.

    cPanel.net Support Ticket Number:
     
  16. dwayrynen

    dwayrynen Member

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    I just noticed that we are receiving this same error when running /scripts/upcp.

    No offense, but our name servers have been infinitely more stable than the ones that cpanel wants to install by default.
    We run four here (two just for our cpanel servers) and they just do not go down or have outages, but we (haven't all of us?) experienced the outages with the default servers. I can't count the number of times I've run through an upgrade for a customer to have it fail because the cpanel name servers are not reachable. Testing during the failures shows black holes on the last hops into the cpanel colo area...

    Since we pay a lot of money per month to DarkOrb, I would like an explanation why our cpanel servers are now not supported because we use our own name severs? That's just silly.

    Darin

    cPanel.net Support Ticket Number:
     
  17. cPanelNick

    cPanelNick Administrator
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    It has nothing to do with thats in the file, just the fact that its chattr +i

    cPanel.net Support Ticket Number:
     
  18. Website Rob

    Website Rob Well-Known Member

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    Why would DarkOrb be interested in having access to make changes in a Server's resolv.conf file?

    cPanel.net Support Ticket Number:
     
  19. ciphervendor

    ciphervendor Well-Known Member

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    Probably to remove machines with legacy cpanel settings. (i.e. having darkorbs dns servers listed...probably causing a shit load of traffic to their servers.)

    cPanel.net Support Ticket Number:
     
  20. Website Rob

    Website Rob Well-Known Member

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    That doesn't compute.

    Do I understand correctly that a Cpanel install will automatically created a 'resolv.conf' file with DarbOrb IPs being listed? Haven't done a Cpanel install myself, but have seen many posts referencing DarkOrb IPs being listed. It is then up to the Server Admin to manually make changes. Hence the notice in WHM to make the changes if not done already.

    I have yet to hear anyone mention that a Cpanel update changed anything within their 'resolv.cong' file, so why would DarkOrb be concerned about having access to write to it?

    cPanel.net Support Ticket Number:
     
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