This document describes how to use IP across the access router to reach
the Primary Domain Controller (PDC) and Windows Name Service (WINS) server, and
how to set up a PC to reach the WINS server.
Readers of this document should have knowledge of these topics:
The information in this document is based on these software and
Note: In most cases, you will use domains, and not workgroups (WINS and
NetBIOS over TCP (NBT), for example, work without domains).
The information in this document was created from the devices in a
specific lab environment. All of the devices used in this document started with
a cleared (default) configuration. If your network is live, make sure that you
understand the potential impact of any command.
For more information on document conventions, refer to the
Technical Tips Conventions.
This section provides the required background information for you to
proceed with this document.
To set the workgroup name to be the domain name, complete these
On the PC running Windows 95, click the Start
button, select Control Panel, then click
From the network components list, select Client for
Click the Properties button.
When the client window is displayed, type your domain name in the
Windows 95 Domain box. Click OK.
You need to ensure that the master browser is disabled on all computers
that have Windows 95 installed on the broadcast domain. This is because, if you
do not do so, they will break browsing for all computers on that wire, and
render them invisible to the domain browsing. Complete these
Click the Start button, select
Settings, and click Control
In the Network window, select TCP/IP <card manufacturer
and model> Adapter.
Click the Properties button.
In the TCP/IP Properties window, click the
If there are any entries for Master Browser, select the entries,
and change the value to Off.
Here is the network diagram that represents the general setup described
in this document:
If the user uses Async or Integrated Service Digital Network (ISDN) to
dial in from an individual end host, and the user wants to browse, you need to
complete the steps in the Set the Workgroup Name to be
the Domain Name and Disable the Master
Browser sections. You will also need to provide RFC1877 information
through global commands on the router that accepts the dialing connection:
Set async-bootp dns-server x.x.x.x
(x.x.x.x is the DNS server).
Set async-bootp nbns-server y.y.y.y
(y.y.y.y is the WINS server).
Note: It is recommended that you use domains.
Note: If you cannot use domains, you need to flood broadcasts. This is not
yet possible on Async lines.
On LAN interfaces, complete these steps:
Run these commands:
ip forward-protocol udp
ip forward-protocol udp
Next, configure bridging on all interfaces that require flooding.
This will create a Spanning-Tree to flood IP broadcasts. The command reference
manual for the ip forward-protocol spanning-tree
Packets must meet the following criteria to be considered for
The packet must be a MAC-level broadcast.
The packet must be an IP-level broadcast; that is, an all-network
broadcast (255.255.255.255) or major network broadcast (188.8.131.52, for
The packet must be a Trivial File Transfer Protocol (TFTP),
Domain Name Service (DNS), Time, NetBIOS, ND, BOOTP packet, or a User Data
Protocol (UDP) specified by the ip forward-protocol udp global configuration
The Time-To-Live (TTL) value for the packet must be at least two.
A flooded UDP datagram is given the destination address specified by
the ip broadcast-address interface configuration
command on the output interface. The destination address can be set to any
desired address. Thus, the destination address can change as the datagram
propagates through the network. The source address is never changed. The TTL
value decreases. After a decision has been made to send the datagram out on an
interface (and the destination address possibly changed), the datagram is
handed to the normal IP output routines, and is therefore subject to access
lists, if they are present on the output interface.
The ip forward-protocol spanning-tree
command uses the database created by the bridging Spanning-Tree Protocol (STP).
Therefore, the transparent bridging option must be in the routing software. In
addition, bridging must be configured on each interface that must participate
in the flooding in order to support this capability. If an interface does not
have bridging configured, it still will be able to receive broadcasts, but it
will never forward broadcasts received on that interface. Also, it will never
use that interface to send broadcasts received on a different interface.
If no actual bridging is required, you can configure a type-code
bridging filter that will deny all packet types from being bridged. Refer to
the Configuring Transparent Bridging chapter in the
and IBM Networking Configuration Guide for more information about using
access lists to filter bridged traffic.
Note: You can use the Find feature in your browser to locate the section
The Spanning-Tree database is still available to the IP forwarding code
to use for the flooding. The Spanning-Tree based flooding mechanism forwards
packets whose contents are all ones (255.255.255.255), all zeros (0.0.0.0),
and, if subnetting is enabled, all networks (184.108.40.206 as an example in
the network number 220.127.116.11). This mechanism also forwards packets whose
contents are the zeros version of the all-networks broadcast when subnetting is
enabled (for example, 18.104.22.168).
For IPX-based NetBIOS, issue the ipx
type-20-propagation command to allow input and output of type 20
propagation packets on all interfaces for browsing to work. Type 20 packets are
subject to loop detection and control as specified in the IPX router
For NetBIOS Extended User Interface (NetBEUI) based NetBIOS, all
participating interfaces need to bridge.
For more details on NetBIOS over IP related issues, see
Domain Browsing with TCP/IP and LMHOSTS Files
Alternatively, you can browse to the Microsoft support site, and search
for article Q150800, which is titled Domain Browsing
with TCP/IP and LMHOSTS Files.