The
Windows Internet Naming Service (WINS) has a long history in Microsoft
networks. In the beginning, Microsoft networks were primarily
broadcast-based, using protocols such as NetBEUI to identify local
computers. If a user on a Windows client wanted to find a system by
name, the Windows client would send out a broadcast message by name, and
if the system was on the same network, it would respond so the two
systems could establish a connection and begin communication. The
problem with this type of name resolution was that it did not scale
beyond multiple subnets, and with today’s networks, broadcast messages
can be blocked by local server and workstation firewalls and
anti-malware software. With the adoption of TCP/IP as an easily routable
protocol, the need to translate NetBIOS
or Windows computer names to IP addresses became a reality. This need
gave rise to the development of the Windows Internet Naming Service
(WINS).
WINS provided a
central database that can be referenced when a client system is looking
up another system by hostname, and that is the key difference between
WINS and DNS, hostname versus fully qualified name. As an example of
this, a server named SERVER10 in the companyabc.com domain would have a
WINS record named “SERVER10” and a DNS record in the companyabc.com DNS
zone named “server10.companyabc.com.”
Understanding the Need for Legacy Microsoft NetBIOS Resolution
WINS is effectively a
simple database of NetBIOS names and their corresponding IP addresses.
Some additional information, such as domain name, server type or service
type, and so on, can be determined as well, from the 16th byte in a
NetBIOS name stored in WINS.
WINS is considered legacy in the
Microsoft world because NetBIOS resolution is being phased out in favor
of the domain name system (DNS) form of name resolution. However, it is
difficult to divorce WINS from modern networks because of the reliance
on WINS by down-level (pre-Windows 2000) clients, legacy applications,
and even some Microsoft services, such as the Distributed File System
(DFS), that utilize NetBIOS resolution by default. Also, many
Independent Software Vendors, or ISVs, develop their software for
Microsoft networks, but their test networks sometimes only include a
single network with no firewalling between systems. When these software
applications are deployed on enterprise networks, they can fall short in
name resolution results, and deploying WINS might be the only viable
solution.
Exploring WINS and DNS Integration
DNS can use the WINS
database to provide for quasi-DNS resolution of WINS clients. This means
that if a name resolution request is sent to a DNS server to resolve client1.companyabc.com, for example, the DNS server will first look in the companyabc.com zone. If no record exists for client1.companyabc.com,
the DNS server will perform a lookup on the WINS database for CLIENT1;
if a WINS record exists, the DNS server will take this IP address and
send it back to the DNS client as client1.companyabc.com, as illustrated in Figure 1.
This functionality must be
enabled on the DNS server because it is not configured by default. This
feature is configured on a zone-by-zone basis; however, if the forward
lookup zone is an Active Directory–integrated zone, each Windows Server
2008 R2 DNS server hosting this zone will copy this WINS setting. To
enable WINS resolution on a DNS server, follow these steps:
1. | On a server running DNS, open the DNS MMC snap-in (Start, Administrative Tools, DNS).
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2. | Navigate to DNS\<Servername>\Forward Lookup Zones.
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3. | Right-click the zone in question and click Properties.
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4. | Choose the WINS tab.
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5. | Select the Use WINS Forward Lookup check box.
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6. | Enter
the IP address of the WINS server(s) to be used for resolution of names
not found in DNS, and click Add to save the changes, as illustrated in Figure 2.
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7. | If
you are replicating this zone between DNS servers that are not running
Windows Server 2008 R2 DNS services, make sure to check the box labeled
Do Not Replicate This Record. This prevents the records from being
replicated to other servers during zone transfers.
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8. | Click OK to finish and return to the DNS Manager page.
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Reviewing Changes in Windows Server 2008 R2 WINS
Although the overall
function of WINS has not changed significantly in Windows Server 2008
R2, some additions to the management tools allow for increased
functionality and capabilities:
Advanced search capabilities for WINS databases—
Previous implementations of WINS had simplistic search capabilities
that were limited to simple keyword searches of NetBIOS records in the
database. The search engine for WINS has been updated in Windows Server
2008 R2 to support more advanced search parameters, thus giving
administrators more flexibility in searching for specific records.
WINS pull record filtering and replication partner acceptance—
Instead of entire transfers of all records on other servers,
replication can be limited to only those records owned by a specific
server, thus excluding extraneous records from littering a WINS
database.
In addition to these
advances in Windows Server 2008 R2, Windows 2000 introduced enhancements
to WINS, such as an updated database engine, persistent connections,
manual tombstoning, and other improvements.
