Re: Change IP subnet for a site

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Thanks for the confirmation, will be going back to them to see if they
allowed for subnet changes in their short-sighted subnet planning:-)

Phil

"Herb Martin" wrote:

> > The only problem being that the network is part of a private network in
> the
> > hands of an another service provider that we as the managed service can't
> > change. ie we tell them a site needs a block of 512 instead of 256 and
> they
> > tell us the new allocation. There maybe a situation where not all of the
> > clients are connected, but I have to allow for the possibility that they
> are
> > all connected at once. If I said the client was in the education sector
> then
> > it may shed some light - they do weird and wonderful things!!
> >
>
> If you have 10,000 users and they tell you something
> that stupid (without trying to understand your problem
> and service the account) then you might tell them you
> are finding a new service provider.
>
> But even if you continue with them, there is NOTHING
> stopping you from using two subnets INSIDE your net;
> you make the change from /23 to /24 at your router(s).
>
>
> --
> Herb Martin, MCSE, MVP
> Accelerated MCSE
> http://www.LearnQuick.Com
> [phone number on web site]
>
> "phawley77" <phawley77@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
> news:297A733A-054E-4F5F-9DE8-020236E4078A@xxxxxxxxxxxxxxxx
> >
> >
> > "Herb Martin" wrote:
> >
> > > "phawley77" <phawley77@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
> > > news:B398D1CE-A45A-44F4-96DE-785205B89329@xxxxxxxxxxxxxxxx
> > > > Would somebody be able to help me with the following scenario:-
> > > >
> > > > A number of sites in a small private distributed network (50 sites,
> 100
> > > DCs
> > > > - 2 per site, 10000 users) need to have their internal IP allocation
> > > changed
> > > > as they have outgrown their allocation (ie changing from a 10.0.1.0/24
> to
> > > a
> > > > 10.2.1.0/23). The AD sites are controlled centrally at the datacentre
> and
> > > can
> > > > be changed centrally, but the changes onsite will be done by an
> engineer.
> > >
> > > You might be better served by adding additional subnets
> > > to the larger sites.
> > >
> > > Especially if only a relatively few sites have more than
> > > 250 clients.
> > >
> > > With the (low) cost of todays routers, and even switch-routers,
> > > it is uncommon to allow even 100 clients on the same broadcast
> > > domain (i.e., subnet.)
> > >
> > > Many people will not even go that high.
> >
> > The only problem being that the network is part of a private network in
> the
> > hands of an another service provider that we as the managed service can't
> > change. ie we tell them a site needs a block of 512 instead of 256 and
> they
> > tell us the new allocation. There maybe a situation where not all of the
> > clients are connected, but I have to allow for the possibility that they
> are
> > all connected at once. If I said the client was in the education sector
> then
> > it may shed some light - they do weird and wonderful things!!
> >
> >
> > >
> > > > I was going to carry this out in the following manner.
> > > >
> > > > Engineer onsite:
> > > >
> > > > 1) Change the IP address, mask, gateway, Primary and secondary DNS
> > > > information on the first DC in the site, followed by the second one.
> > >
> > > The routers must understand this first.
> >
> > The network provider would do this as we do our bit.
> >
> > >
> > > > 2) Delete existing DHCP scope, create new one, change the exclusion
> range
> > > > and lease length, etc.
> > >
> > > I would probably disable (initially) rather than delete the scopes.
> >
> > I agree.
> >
> > >
> > > > 3) Recreate the reverse lookup zone for the new allocation. Reboot the
> > > > servers.
> > >
> > > Or just use a common (single) reverse zone.
> > >
> > > > 4) Have the engineer contact the datacentre to update sites and
> services
> > > > with the new subnet information
> > >
> > > Probably best done earlier if possible. Especially
> > > if you don't have to move subnets but just make them
> > > bigger. Again, though, I would try to avoid this by
> > > spliting the cable segments into multiple subnets.
> >
> > This was the part where i wasn't sure whether to get this done ahead of
> > time, put like i said its likely we will be given a new subnet rather than
> an
> > extension of the old one.
> >
> > >
> > > > 5) Perform ipconfig /registerdns on the two servers on the site to
> update
> > > > DNS to ensure proper DNS registration.
> > >
> > > This only works for Non-DCs and should happen right
> > > after changing the IP -- if you reboot it is automatic.
> > >
> > > > 6) Check Connectivity with the datacentre servers
> > > >
> > > > 7) Reboot clients to ensure they pick up a new IP address from the new
> > > range.
> > >
> > > Ipconfig /renew (works just as well.)
> >
> > Dodgy hardware in places means this command doesn't 'always' work for this
> > client.
> >
> > >
> > > You will also want to find all IP references to servers that
> > > will change addresses, DNS (including forwarder entries),
> > > WINS servers, routers, print devices, etc.
> >
> > I am assure that all references to the servers are by DNS name so should
> be
> > OK.
> >
> > >
> > > > All that said, given that this will be carried out during off hours,
> does
> > > > this method make sense or am I missing something? Also can steps 1 -
> 4 be
> > > > carried out normally, or do the servers need to be rebooted in
> Directory
> > > > restore Mode (a colleague thinks this may be necessary).
> > >
> > > You will want to double-check the DCs (replication etc.)
> >
> > So presumably force a replication afterwards to a DC at the datacentre,
> and
> > back from the datacentre DC?
> >
> > > and the DNS.
> > >
> > > Here are the general guidelines:
> > >
> > >
> > > --
> > > DNS for AD
> > > 1) Dynamic for the zone supporting AD
> > > 2) All internal DNS clients NIC\IP properties must specify SOLELY
> > > that internal, dynamic DNS server (set.)
> > > 3) DCs and even DNS servers are DNS clients too -- see #2
> > > 4) If you have more than one Domain, every DNS server must
> > > be able to resolve ALL domains (either directly or
> indirectly)
> > >
> > > netdiag /fix
> > >
> > > ....or maybe:
> > >
> > > dcdiag /fix
> > >
> > > (Win2003 can do this from Support tools):
> > > nltest /dsregdns /server:DC-ServerNameGoesHere
> > > http://support.microsoft.com/kb/q260371/
> > >
> > > Ensure that DNS zones/domains are fully replicated to all DNS
> > > servers for that (internal) zone/domain.
> > >
> > > Also useful may be running DCDiag on each DC, sending the
> > > output to a text file, and searching for FAIL, ERROR, WARN.
> > >
> > > Single Label domain zone names are a problem Google:
> > > [ "SINGLE LABEL" domain names DNS 2000 | 2003 microsoft: ]
> > >
> >
> > Cool, so apart from the minor changes, and given the constraints, then the
> > process should be OK right?
> >
> > >
> > > --
> > > Herb Martin, MCSE, MVP
> > > Accelerated MCSE
> > > http://www.LearnQuick.Com
> > > [phone number on web site]
> > >
> > >
> > >
>
>
>
.

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