Re-subnetting a network

We currently use the class C 192.168.0 for our main office subnet. I would
like to migrate the network to the 10. private range for two reasons: we are
running out of ip addresses; and using 192.168.0 has caused us some issues
with users that take their laptops home to a wireless network which
frequently uses the same ip range.

What would I need to go through to do this that would cause the least
disruption. I know I will have to re-assign static addresses and change the
dhcp server scope. Are there any issues with regard to Active Directory or
other infrastructure issues I need to be concerned about?

In news:(E-Mail Removed),
Jeff Hofstetter <(E-Mail Removed)> stated, which I commented on below:
> We currently use the class C 192.168.0 for our main office subnet. I
> would like to migrate the network to the 10. private range for two
> reasons: we are running out of ip addresses; and using 192.168.0 has
> caused us some issues with users that take their laptops home to a
> wireless network which frequently uses the same ip range.
>
> What would I need to go through to do this that would cause the least
> disruption. I know I will have to re-assign static addresses and
> change the dhcp server scope. Are there any issues with regard to
> Active Directory or other infrastructure issues I need to be
> concerned about?

No issues, just have to plan it correctly. But I can;t see how you will gain
IP addresses just by changing the block from a current /24 to another /24
unless you are changing the mask? If changing the mask, then I assume you
will be familiar with taking it into the next octet, such as 192.168.10.0/26
to 192.168.11.0/26. That will give you 512 IPs.

PLan it out. The first thing is inventory static machines. Then change the
IP of the DC(s). Ensure they register by doing this:
ipconfig /registerdns
net stop netlogon
net start netlogon

Check DNS to insure the A record for the machine (it's name) got updated,
and the LdapIpAddress (shows up as 'same as parenta) for each DC registered.
Check the _msdcs.gc folder to insure the GC got registered. If the old one
is in there, manually delete it.

Once that's done, change the DHCP scope. Then change all the static
machines. You may need to manually ipconfig /release and ipconfig /renew the
clients.

--
Ace

This posting is provided "AS-IS" with no warranties or guarantees and
confers no rights.

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Ace Fekay, MCSE 2003 & 2000, MCSA 2003 & 2000, MCSE+I, MCT, MVP
Microsoft MVP - Directory Services
Microsoft Certified Trainer

Infinite Diversities in Infinite Combinations
Assimilation Imminent. Resistance is Futile
"Very funny Scotty. Now, beam down my clothes."

The only thing in life is change. Anything more is a blackhole consuming
unnecessary energy. - [Me]

Umm Ace,
I think you have your CIDR notation a little off there. /24 to /26 loses IPs
not gains. Maybe you meant /23 ? But hey, I could be wrong, I always rely on
a subnet calculator nowadays.

And good tip on the DCS. Lots of people forget that the command line can
help you out and end up rebooting all their servers doing stuff like this.

Of course if you are out growing a class c network, my whole take is grab a
router and a few high capacity switches and break into at least three
subnets. Put all your servers in the "middle" subnet and break the clients
out to the two (or more) "leaf" subnets/collision domains.
Router doesn't need to be fancy, but I would recommend using a layer three
capable high capacity VLAN switch for flexibility. But a NetView or other
basic business class router will do.

Provided you have the physical capability to do this, i.e. a
punchdown/patchpanel feeding to a switch rack. Which is pretty standard.


--
Manny Borges
MCSE NT4-2003 (+ Security)
MCT, Certified Cheese Master

There are 10 kinds of people in the world. Those who do understand binary
and those who don't.

"Ace Fekay [MVP]"
<PleaseSubstituteMyActualFirstName&LastNameHere@ho tmail.com> wrote in
message news:(E-Mail Removed)...
> In news:(E-Mail Removed),
> Jeff Hofstetter <(E-Mail Removed)> stated, which I commented on below:
>> We currently use the class C 192.168.0 for our main office subnet. I
>> would like to migrate the network to the 10. private range for two
>> reasons: we are running out of ip addresses; and using 192.168.0 has
>> caused us some issues with users that take their laptops home to a
>> wireless network which frequently uses the same ip range.
>>
>> What would I need to go through to do this that would cause the least
>> disruption. I know I will have to re-assign static addresses and
>> change the dhcp server scope. Are there any issues with regard to
>> Active Directory or other infrastructure issues I need to be
>> concerned about?
>
> No issues, just have to plan it correctly. But I can;t see how you will
> gain IP addresses just by changing the block from a current /24 to another
> /24 unless you are changing the mask? If changing the mask, then I assume
> you will be familiar with taking it into the next octet, such as
> 192.168.10.0/26 to 192.168.11.0/26. That will give you 512 IPs.
>
> PLan it out. The first thing is inventory static machines. Then change the
> IP of the DC(s). Ensure they register by doing this:
> ipconfig /registerdns
> net stop netlogon
> net start netlogon
>
> Check DNS to insure the A record for the machine (it's name) got updated,
> and the LdapIpAddress (shows up as 'same as parenta) for each DC
> registered. Check the _msdcs.gc folder to insure the GC got registered. If
> the old one is in there, manually delete it.
>
> Once that's done, change the DHCP scope. Then change all the static
> machines. You may need to manually ipconfig /release and ipconfig /renew
> the clients.
>
> --
> Ace
>
> This posting is provided "AS-IS" with no warranties or guarantees and
> confers no rights.
>
> Having difficulty reading or finding responses to your post?
> Instead of the website you're using, I suggest to use OEx (Outlook Express
> or any other newsreader), and configure a news account, pointing to
> news.microsoft.com. This is a direct link to the Microsoft Public
> Newsgroups. It is FREE and requires NO ISP's Usenet account. OEx allows
> you to easily find, track threads, cross-post, sort by date, poster's
> name, watched threads or subject.
>
> It's easy:
> How to Configure OEx for Internet News
> http://support.microsoft.com/?id=171164
>
> Ace Fekay, MCSE 2003 & 2000, MCSA 2003 & 2000, MCSE+I, MCT, MVP
> Microsoft MVP - Directory Services
> Microsoft Certified Trainer
>
> Infinite Diversities in Infinite Combinations
> Assimilation Imminent. Resistance is Futile
> "Very funny Scotty. Now, beam down my clothes."
>
> The only thing in life is change. Anything more is a blackhole consuming
> unnecessary energy. - [Me]
>

In news:(E-Mail Removed),
Manny Borges <(E-Mail Removed)> stated, which I commented on below:
> Umm Ace,
> I think you have your CIDR notation a little off there. /24 to /26
> loses IPs not gains. Maybe you meant /23 ? But hey, I could be wrong,
> I always rely on a subnet calculator nowadays.

Yep, I went the wrong way! I did mean /23.

Thanks for catching that.

>
> And good tip on the DCS. Lots of people forget that the command line
> can help you out and end up rebooting all their servers doing stuff
> like this.
> Of course if you are out growing a class c network, my whole take is
> grab a router and a few high capacity switches and break into at
> least three subnets. Put all your servers in the "middle" subnet and
> break the clients out to the two (or more) "leaf" subnets/collision
> domains. Router doesn't need to be fancy, but I would recommend using a
> layer
> three capable high capacity VLAN switch for flexibility. But a
> NetView or other basic business class router will do.
>
> Provided you have the physical capability to do this, i.e. a
> punchdown/patchpanel feeding to a switch rack. Which is pretty
> standard.

Good advice!

Ace