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elchermansFlag for Canada

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Domain Controller site IP addressing best practices:

When designing a new site, what are the best practices when it comes to IP addressing to allow for easily adding remote sites without having to renumber.

Also what VPN technology works best when adding remote sites.
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Patrick Bogers
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we have 82 sites and we run on a mix of 192.168.x.x / and 172.x.x.x. The 192 addresses are set  up site to site via a VPN tunnel to the 172. Also on some of the larger sites we have created a supernet to allow for more than the 255 addresses. works well
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cwstad2: What hardware do you use for the VPN tunnel and how is performance through said tunnel?

Also why not use part of 10.0.0.0/8 address space?
We've acquired many companies over the years, and there is always a conflict when connecting their subnets to ours, even in a large /8 like the 10-space. 10.10.10.x is a very popular choice I'll have you know :) We basically force them to change their IP's. We used to use a philosophy of Ten-dot-what_#_in_the_us
So 10.6 for Massachusetts, 10.11 for NC, 10.19 for Indiana, etc
http://en.wikipedia.org/wiki/List_of_U.S._states_by_date_of_statehood#Table
Then outside the US, anything in Canada was 10.100, and in EU/Asia etc it was 10.200.
We've kept it up for the most part, we have some weird 10.60, 10.99 but basically each state got it's own /16.
We assimilate any 192.168 or 172.16's into the 10/8, as soon as we can. But sometime you have to have that transition period where you have to terminal service into a box at the other end of the VPN to do your work.
If you use a standard protocol like IPSEC, it won't really matter what VPN device you have, you can partner with hundreds of other manufactures when you both speak the same language. We use Cisco gear, and so does just about everyone we've acquired in the US and abroad.
*Edited to add*
We started using MPLS connections to the remote offices, makes it sooooo much easier to route and setup, look into those kinds of circuits :)
-rich
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btan

To maintain original network assignment and serve as remote network transparent for external access via VPN, the NAT will come in to proxy. That is a initial thoughts but as best practice the network itself as queried should adhere some rules as well or scaling up and also scaling down. This can extend even to IPv4 to IPv6 consideration for NAT64 or DNS64.

Cisco has a document (pdf) stating some of the best practices.

Page 5 - Do check out the Private addressing section where it advices sparingly used and even temporary NAT functionality to reduce the "renumbering" challenges when network interconnected.

Page 6-7 - Have example on multiplexing IP and share dynamic port assignment is also something to consider as application may varied and exhaustion can come easily if assignment is not thought through. Also remote access use case is shared.
i would recommend MS official way on IP addresses planning against AD sites.

Creating a Site Design
http://technet.microsoft.com/en-us/library/cc736820%28v=ws.10%29.aspx

Using Catch-All Subnets in Active Directory
http://technet.microsoft.com/en-us/magazine/2009.06.subnets.aspx