Changing corprate network addressing

Discussion in 'Server Networking' started by Scott Micale, Apr 7, 2008.

  1. Scott Micale

    Scott Micale Guest

    I am in the process of changing our corporate network around. The way it is
    now is I have a 192.168.1.x network with a subnet and another
    network with a 192.168.2.x network with a subnet. I want to
    bring all the clients and DC's from the 192.168.2.x network into the
    192.168.1.x network and then switch the subnet to The DC's
    in the 192.168.2.x network are also DNS servers if I bring them into the
    other network and change their IP's to match the new network will there be
    anything in DNS I will need to reconfigure or will they know to update the
    DNS records automatically? Will there be anything else I will need to be
    aware of when doing this? I plan to use DHCP reservations for all these
    client and DC's coming over from the other network.

    Scott Micale, Apr 7, 2008
    1. Advertisements

  2. 1. Get away from the heavily over-used low numbers in the third octet. Go
    above 10 and don't use "10", is over used as well.

    2. Don't get in a rush. You may spend a week or more on the move. Move
    machines in small chunks. DNS and WINS should adjust automatically,...just
    don't "rush" it.

    3. Create a new IP Segment and have a *real* LAN Router between them.

    4. Create a new Scope (No Superscopes!) on the DHCP Server and configure the
    DHCP Helper Address on the LAN Router so it will forward the DHCP queries.
    Use DHCP **only** for Clients,...not Servers,...not "network devices".

    5. Move Client machines first. Usually as simple as moving a patch cable
    in the MDF/IDF to another switch port on the other subnet.

    6. Move the servers (not DCs) a couple at a time so you can keep up with
    connectivity problems if they come up.

    7. Move DCs last and move them one at a time. Adjust the DHCP Scope to the
    new IP# of the DC and manually do it on the non-DHCP devices. Release/Renew
    the DHCP Clients. Allow the network to "settle in" for a few hours or a day
    each time you move one.

    Phillip Windell

    The views expressed, are my own and not those of my employer, or Microsoft,
    or anyone else associated with me, including my cats.
    Phillip Windell, Apr 7, 2008
    1. Advertisements

  3. Scott Micale

    Scott Micale Guest

    Thanks Phillip I will stick to these rules you laid out and follow them.
    should be a pretty smooth transition. I have pretty much already done the
    clients I just wanted to get an idea on what was thought of my DC's.

    Thanks again!
    Scott Micale, Apr 7, 2008
  4. Scott Micale

    Anteaus Guest

    Advice given is good, however I would add that you have ONE network at
    present, not two. The mask means that the 3rd and 4th octets
    combine to form one contiguous range of computer numbers.

    As such you DON'T need a router to connect the two ranges, as they aren't

    -In which case, unless you have a pressing reason to change such as another
    clashing range elsewhere, it would be better to leave as-is.
    Anteaus, Apr 7, 2008
  5. Ah, yes, that's right.

    So the whole migration could be done by moving all the machines into a range
    of say and since the mask is
    everything should continue working.

    When everything is moved then just change the mask to
    Everything will still be in the same segment and should still keep working.

    Phillip Windell

    The views expressed, are my own and not those of my employer, or Microsoft,
    or anyone else associated with me, including my cats.
    Phillip Windell, Apr 8, 2008
  6. Scott Micale

    Scott Micale Guest


    I am in the process now of making my convertion, but I am stuck at my
    beginning point and hopefully you can help me out here. I have the original
    scope setup in my DHCP server. I was hoping that I could just change or
    edit the oringinal scope from to, but it appears I
    can't. My problem is I have reservations already setup on this scope and I
    do not want to loose those reservations. If I have to create or delete this
    existing scope how can I get that reservation list in the new scope so I
    don't have to re-enter everything? Remember I have Site A as 192.168.1.x and site B 192.168.2.x and I want to remove the site
    B network and bring them into Site A network and change the subnet mask to

    Let me know what you think I can do.

    Scott Micale, May 9, 2008
  7. Scott Micale

    Scott Micale Guest

    My problem though is that I already have DHCP reservations setup in the
    192.168.1.x network. I don't want to have to re-create those reservations.
    Is there a way to keep everything in the 192.168.1.x network but just change
    the subnet mask to Every system that we have on the network
    has to have a specific IP address to allow them to access our inventory
    management system to uses Specific licenses that match the client IP
    Scott Micale, May 9, 2008
  8. Scott Micale

    Scott Micale Guest


    Is the subnet mask on my scope in the registery somewhere so that I could
    just change it from to
    Scott Micale, May 9, 2008
  9. Scott Micale

    Scott Micale Guest


    I went through my registry and I have found several places in it that show
    my subnet mask of I just did a registry search for DHCP and it
    brought back about 5 or 6 locations where it shows that subnet setting for
    DHCP. You think I could just change all those to the new DHCP Subnet Mask I
    want and it would update all my clients?

    Scott Micale, May 9, 2008
  10. Scott Micale

    Scott Micale Guest


    Have you read any of my posts on the registry changes? is this possible to
    make it work?

    Scott Micale, May 12, 2008
  11. I just got back from vacation.
    It's at the end of the day and I just now saw the posts. I have time for a
    quick answer. We can look at it again tomorrow.

    1. You can't change the mask in the Scope
    2. Don't screw with the registry. I doubt you would get the results you want
    but cannot verify that. But you might make a really cool mess though.
    3. If you have so many Reservations that this is a problem,...then,
    have too many Reservations. The whole idea of Reservations is to only have
    a few. If you have a lot,...then you should have statically assigned the
    machines in the first place. Now would be an opportunity to correct that.
    4. Statically assign the machines and forget the Reservations. Determine if
    some of the machines *really* need to always have the same IP#,...if you can
    do without that then just let as many as you can switch to Dynamic.
    5. Create Reservations for the remaining machines that it would be too much
    trouble to do otherwise.
    6. Include Statically assigned addresses in the Exclusions Ranges.

    Phillip Windell

    The views expressed, are my own and not those of my employer, or Microsoft,
    or anyone else associated with me, including my cats.
    Phillip Windell, May 12, 2008
  12. Scott Micale

    Scott Micale Guest


    Well you are now making my life more difficult! :) I had most of my PC set
    with Static addresses, but now we are in the process of switching internet
    providers so I figured having everyone on DHCP with reservations it would
    make the switch easier because I would just have to make a few tweaks in my
    DHCP server for the gateway address and then be done. Now you are saying
    that I need to not use reservations. Well in another post a person left me
    a response to try a script that would change it. So I think I am gonna give
    that a shot later and hope that does it for me. How vacation? Go anywhere
    Scott Micale, May 13, 2008
  13. It is a "different" way to do it,...not an "easier" way, you are
    seeing. If machines require having the same address all the time then your
    choice is Static or DHCP Reserved. If the address shceme changes, then you
    are either recreating Reservations or manually reconfiguring the TCP/IP
    specs of the machine, choice,...they are both a lot of work.

    Personally I choose to not have my network infrastructure have its
    "survival" dependent on if a DHCP Server remains "alive" and does die on me
    someday. Machines that survive by Reservations are therefore dependent on
    the DHCP Server,...but Static machines depend on no one. With only a few
    Reservations, all of my servers, networking devices, and anything else tied
    to the infrastructure run Static Addresses and will continue to survive even
    with a total loss of DHCP,...yours will not. Yours is also suseptable to a
    rogue DHCP Server being introduced into the system, some plugging in
    a simple Linksys box into the LAN without disabling the DHCP Service first.
    That would make quite a mess when it gives all your Servers and LAN Device
    the wrong IP because it would not honor the Reservations.
    I went to my backyard,...

    .....striped the back wall of the house down to the wall studs,...removed the
    electrical Power Service after the power company cut the power,
    the wall with new wood,...covered it with "house wrap" material,...replaced
    two Window Assemblies,...installed new 100 amp Power Service equipment,..had
    the power company reconnect the power,... a raincoat, the pouring rain,...over a three day period.

    I think I would have rather created DHCP Reservations.


    Phillip Windell

    The views expressed, are my own and not those of my employer, or Microsoft,
    or anyone else associated with me, including my cats.

    Phillip Windell, May 14, 2008
  14. Scott Micale

    Scott Micale Guest


    I am cracking up reading your post! Man I too definitely would rather be
    creating DHCP Reservations then doing what you just did! Why in the world
    did you have to do all that? I have done a lot of remodeling to my home as
    well, but nothing like that! Hope everything turned out well for you. I
    will be making my conversion tomorrow night and Wednesday morning. I think
    it is going to go pretty well. I have really thought this all through and
    there should be no hiccups!

    Wish me luck!

    Scott Micale, May 20, 2008
  15. The outer sheeting is plaster drywall (yep, on the outside) covered with a
    metal skin and there was very little insulation. So I am striping it down
    to nothing and starting over and doing it in a more conventional way with
    wood outer sheeting, better insulation, and regular new drywall on the
    inside, then new siding, at least the outer walls will be like a new
    house when I am finished. I didn't plan well with respect to the weather
    but those were the days I took off from work to do it and had the
    arrangements made with the power company to disconnect/reconnect, I was
    kinda stuck with it.
    Ok,..good luck with it Scott!

    Phillip Windell

    The views expressed, are my own and not those of my employer, or Microsoft,
    or anyone else associated with me, including my cats.
    Phillip Windell, May 20, 2008
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.