+ Post New Thread
Page 1 of 2 12 LastLast
Results 1 to 15 of 21
Windows Server 2000/2003 Thread, DNS/DHCP ip Conflicts in Technical; I hope some one can help as this is driving me nuts. We had to get a new range added ...
  1. #1

    Join Date
    Oct 2006
    Posts
    106
    Thank Post
    9
    Thanked 3 Times in 3 Posts
    Rep Power
    16

    DNS/DHCP ip Conflicts

    I hope some one can help as this is driving me nuts.

    We had to get a new range added to our network as we ran out of addresses, this may not be the cause but we are getting ip conflicts (bad addresses) in dhcp and when doing a nslook up on the addresses, it throws back multiple machine names.

    I went to a pc which had a ip confict and checked to see what dhcp server it was getting its address from and it was correctly set to the dhcp server. it was using the 2nd nic card set on the new range, which was inline with the ip the laptop had been given.

    Taking a step back we had to give the dhcp server 2 nics one on each ip range.

    when i tried to do a nslook up on the laptop for the address it had gotten the dhcp address from it couldn't find it.

    So i have these problems

    Ip conflicts about 10-15 on each range

    Dns problems.

    Any ideas? I can post more info if needed.


    Rob.

  2. #2
    Disease's Avatar
    Join Date
    Jan 2006
    Posts
    1,092
    Thank Post
    117
    Thanked 70 Times in 48 Posts
    Rep Power
    56
    Have you tried 'Scavenging Stale Records' on your DNS server to remove the duplicate entries in DNS?

  3. #3
    Kogelkopper's Avatar
    Join Date
    Nov 2008
    Posts
    27
    Thank Post
    3
    Thanked 1 Time in 1 Post
    Rep Power
    0

    A solution?

    A solution maybe, to throw away the leases in every scope, just to be sure, after working ours
    The following day, the pc's will "ask" for a new IP address.

  4. #4

    Join Date
    Oct 2006
    Posts
    106
    Thank Post
    9
    Thanked 3 Times in 3 Posts
    Rep Power
    16
    Quote Originally Posted by Disease View Post
    Have you tried 'Scavenging Stale Records' on your DNS server to remove the duplicate entries in DNS?
    Done that. did not work.

  5. #5

    Join Date
    Oct 2006
    Posts
    106
    Thank Post
    9
    Thanked 3 Times in 3 Posts
    Rep Power
    16
    Quote Originally Posted by Kogelkopper View Post
    A solution maybe, to throw away the leases in every scope, just to be sure, after working ours
    The following day, the pc's will "ask" for a new IP address.
    Tried that as well.
    Thanks for the replays though.

  6. #6
    Kogelkopper's Avatar
    Join Date
    Nov 2008
    Posts
    27
    Thank Post
    3
    Thanked 1 Time in 1 Post
    Rep Power
    0
    Hi Rob,

    Can you specify the actual settings in your DHCP server?

  7. #7
    azrael78's Avatar
    Join Date
    Sep 2007
    Location
    Devon
    Posts
    383
    Thank Post
    47
    Thanked 37 Times in 33 Posts
    Rep Power
    21
    A good idea to assist in your problem would be to disable (temporarily) dynamic DNS.

    For anything that requires a FQDN - give it a manual DNS entry.

    The reason I say disable it - simple, it sounds like you have multiple issues regarding DHCP AND DNS, if you take DNS out of the equation - it can make the problem easier to handle and repair.

    If you can post your DHCP server settings, we can help you more.

    It sounds though - like you added another DHCP scope without reconfiguring the subnet masks - check the DHCP logs.

    Find a client that is troublesome - release the address and renew while looking at the log. It may well give you an idea.

    What's your network infrastructure? We talking 1 DHCP server, no routers, no subnets?

    Az

  8. #8

    Join Date
    Oct 2006
    Posts
    106
    Thank Post
    9
    Thanked 3 Times in 3 Posts
    Rep Power
    16
    Thanks for the response guys here is the info you asked for, if i miss any thing just ask.

    Scope 1

    10.4.108.71 -10.4.111.200
    sub net mask 255.255.252.0

    lease time set to 16 hours

    Dns tab

    enable dns dynamic updates is ticked and always dynamically update dns a and ptr records is selected

    discard a and ptr records when lease is deleted is ticked

    dynamically update dns a and ptr records for dhcp clients that do not request updates is also ticked.

    Advanced tab

    dhcp only is selected

    Scope options

    router 10.4.11.254
    dns servers 10.4.108.2, 10.4.108.5, 10.4.108.6
    Domain name is added on this range

    Scope 2

    10.4.224.1 -10.4.231.253
    255.255.248.0

    lease time set to 16 hours

    Dns

    enable dns dynamic is ticked
    dynamically update dns a and ptr records is selected
    always dynamically update dns a and ptr records is not selected
    discard a and ptr records when lease is deleted is ticked

    Dynamically update dns a and ptr records for dhcp clients that do not request updates in not ticked.

    Advanced

    Dhcp only

    Scope options

    router 10.4.31.254
    dns servers 10.4.108.2, 10.4.108.5, 10.4.108.6
    no domain name

  9. #9
    azrael78's Avatar
    Join Date
    Sep 2007
    Location
    Devon
    Posts
    383
    Thank Post
    47
    Thanked 37 Times in 33 Posts
    Rep Power
    21
    Try this - see if it helps.

    On the DHCP Server console - right click the DHCP server and go to Properties.
    Go to the Advanced Tab.
    Set 'Conflict Detection Attempts' to 1.

    This means when your clients will try to renew their IP, the DHCP server will first check to see if the IP the client is asking for is already in use by someone else.

    If it is - it will allocate the next available.

    As I said previously, you should probably turn Dynamic DNS off for now (DHCP Server console again).

    What strikes me as a little odd is that you have 1 subnet using 255.255.248.0 and another using 255.255.252.0.

    These 2 subnet masks cover different ranges which may well be part of your confusion.

    What is your TOTAL IP range? (As in, what numbers can you use)

    Az

  10. #10

    maniac's Avatar
    Join Date
    Feb 2007
    Location
    Kent
    Posts
    3,051
    Thank Post
    209
    Thanked 427 Times in 307 Posts
    Rep Power
    144
    Is it not possible to move the entire domain onto the new scope - it has a lot more addresses on it than the old one. that way you wouldn't get any of these sorts of problems. As it stands at the moment with the subnets that you've selected, the two scopes won't be able to talk to each other as far as I can work out.

    Mike.

  11. #11
    azrael78's Avatar
    Join Date
    Sep 2007
    Location
    Devon
    Posts
    383
    Thank Post
    47
    Thanked 37 Times in 33 Posts
    Rep Power
    21
    Mike: That's what I was wondering - you could simply superscope them both couldn't you? Giving them the shared subnet?

    Az

  12. #12

    Join Date
    Oct 2006
    Posts
    106
    Thank Post
    9
    Thanked 3 Times in 3 Posts
    Rep Power
    16
    The 2 ranges were the ones given to us from the swgfl, i think as im not totally understanding every thing here but would the router enable the 2 subnets to talk to each other?

    i have changed the setting to 1 it was on 2m will see if that makes any difference.

    The 2 sub nets not talking to each other would make sense when I tried to do a ns look up on the dhcp server the pc had got its duplicate ip from and it couldn't find it, it was on the same range though..

    A question, if a pc went to the server for an address and the first range was all used would it then go to the 2nd range and take an address from there or would it just use one in its full range?
    Last edited by rob101; 3rd November 2009 at 02:18 PM.

  13. #13

    Michael's Avatar
    Join Date
    Dec 2005
    Location
    Birmingham
    Posts
    9,262
    Thank Post
    242
    Thanked 1,568 Times in 1,250 Posts
    Rep Power
    340
    As already mentioned, I don't think those two ranges will talk. You're much better off migrating everything to your new second scope.

  14. #14

    Join Date
    Oct 2006
    Posts
    106
    Thank Post
    9
    Thanked 3 Times in 3 Posts
    Rep Power
    16
    Quote Originally Posted by Michael View Post
    As already mentioned, I don't think those two ranges will talk. You're much better off migrating everything to your new second scope.
    That's a crap load of work.

    They must be talking to stuff on the other range as we have pc's with the 10.4.224 range talking to the servers that are all on the 10.4.108 range.

    Still confused.

  15. #15

    Michael's Avatar
    Join Date
    Dec 2005
    Location
    Birmingham
    Posts
    9,262
    Thank Post
    242
    Thanked 1,568 Times in 1,250 Posts
    Rep Power
    340
    I suppose it really depends just how many devices have static IPs doesn't it? APs, printers, admin workstations, servers. Can't think of much else.

SHARE:
+ Post New Thread
Page 1 of 2 12 LastLast

Similar Threads

  1. DHCP conflicts from somewhere
    By cromertech in forum Wireless Networks
    Replies: 10
    Last Post: 30th September 2009, 12:38 PM
  2. DHCP not giving out second DNS to XP
    By ZeroHour in forum Windows Server 2008
    Replies: 9
    Last Post: 28th January 2009, 11:05 AM
  3. DNS DHCP Course
    By KWestos in forum Courses and Training
    Replies: 2
    Last Post: 3rd September 2008, 10:57 AM
  4. DNS Scavenging and DHCP
    By brahma in forum Windows
    Replies: 8
    Last Post: 29th July 2008, 10:41 PM
  5. DNS/DHCP Issues
    By link470 in forum Windows
    Replies: 1
    Last Post: 11th March 2008, 08:33 AM

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •