Configuring DRAS with Reserved IP Addresses for Private Networks

This article was previously published under Q178538
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Per RFC 1597: Section 3: Private Address Space, The Internet AssignedNumbers Authority (IANA) has reserved the following three blocks of the IPaddress space for private networks: - ,, and -

These network IDs and the associated IP addresses may be used freely inany internal network scheme and will not affect interoperability with theInternet as a whole. In particular, the class C range is the preferredrange to use when configuring the async connectors of Microsoft ExchangeServer.
Each async interface on a Windows NT Server computer requires two (2) ipaddress; one for the server and one for the client of the particularsession. The network ID of the async interface should be such that theasync interface is on a different subnet than the network interface of theserver; as such the unit is multihomed. Using a subnet mask of 255 in thethird octet of the class C address allows 255 networks with 254 hosts oneach network; this facilitates ease of planning and configuration.

For example, connect 3 Exchange sites through the Dynamic Remote AccessService (RAS) connector. Each Exchange Server computer has a single modem.

  1. In the RAS configuration, select a static pool of addresses.
  2. Configure the pools on each server as follows.
          Server_1 and;      Server_2 and      Server_3 and
Thus the RAS server session on each server will get the .1 address and theclient session will be assigned the .2 address.

Article ID: 178538 - Last Review: 10/07/2013 16:21:04 - Revision: 3.3

Microsoft Exchange Server 4.0 Standard Edition, Microsoft Exchange Server 5.0 Standard Edition, Microsoft Exchange Server 5.5 Standard Edition

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