Article ID: 176280
Article Last Modified on 9/22/2005
APPLIES TO
- Microsoft SNA Server 3.0 Service Pack 4
- Microsoft SNA Server 4.0
- Microsoft SNA Server 3.0 Service Pack 2
This article was previously published under Q176280
SYMPTOMS
The TN3270 service included with SNA Server version 3.0 (and later) allows an administrator to restrict access to specific TN3270 clients by assigning either IP addresses or host names to LUA LUs/Pools assigned to the TN3270 service.
When you restrict access to TN3270 sessions using host names, TN3270 clients fail to connect to the TN3270 service if the host name used is the NETBIOS name (that is, computer name) of the client. The exact error that the client sees will depend on the TN3270 emulator being used.
The 3270 applet included with SNA Server 3.0 Service Pack 2 when configured for TN3270E Server Connection returns the following error when this problem occurs:
A TN3270 internal trace returns the following message to the TN3270 client:
CAUSE
If the TN3270 service is configured for Use Name Resolution, it requires the use of fully qualified domain names (FQDNs). The TN3270 service does not allow clients to connect to LUA LUs/Pools that are configured with client NETBIOS names.
Note: You must select the Use Name Resolution option under TN3270 Server properties when you restrict access via host names.
WORKAROUND
Specify the fully qualified domain names in the LUA LUs/Pools properties when restricting access by host name. A simple way of determining the FQDN for a client is to Ping the client. For example:
c:\> ping client1 Pinging client1.dns.company.com [ip address] with 32 bytes of data: Reply from <ip address>: bytes=32 time<10ms TTL=128 Reply from <ip address>: bytes=32 time<10ms TTL=128 Reply from <ip address>: bytes=32 time<10ms TTL=128 Reply from <ip address>: bytes=32 time<10ms TTL=128
In this case, the LUA LU/Pool should be configured with a name of client1.dns.company.com to allow a user on the CLIENT1 system to access this LU/Pool.
STATUS
The TN3270 service has been updated to correctly use both NETBIOS names and FQDNs for name resolution.
Microsoft has confirmed this to be a problem in SNA Server versions 3.0, 3.0 SP1, and 3.0 SP2.
This problem was corrected in the latest SNA Server version 3.0 U.S. Service Pack. For information on obtaining this Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):
S E R V P A C K
MORE INFORMATION
The name resolution method used is determined by the Windows NT Server computer on which SNA Server is installed. There are currently four NetBIOS over TCP/IP name resolution methods: b-node, p-node, m-node, and h-node. For more information about these name resolution methods, please refer to the following Microsoft Knowledge Base article:
119493 NetBIOS over TCP/IP Name Resolution and WINS
To determine which name resolution method is being used by a Windows NT system, use the IPCONFIG utility from a command prompt as shown here:
c:\> ipconfig /all
The IPCONFIG /ALL command will return information similar to the following:
Windows NT IP Configuration
Host Name . . . . . . . . . : server1.companyname.com DNS Servers . . . . . . . . : 123.23.234.123 123.23.235.124 Node Type . . . . . . . . . : Mixed NetBIOS Scope ID. . . . . . : IP Routing Enabled. . . . . : No WINS Proxy Enabled. . . . . : No NetBIOS Resolution Uses DNS : No
Ethernet adapter El90x1:
Description . . . . . . . . : 3Com 3C90x Ethernet Adapter Physical Address. . . . . . : 00-80-C7-55-55-C5 DHCP Enabled. . . . . . . . : Yes IP Address. . . . . . . . . : 124.24.235.123 Subnet Mask . . . . . . . . : 255.255.248.0 Default Gateway . . . . . . : 124.24.235.1 DHCP Server . . . . . . . . : 124.24.235.111 Primary WINS Server . . . . : 123.23.234.125 Secondary WINS Server . . . : 123.23.234.126 Lease Obtained. . . . . . . : Tuesday, January 01, 1998 7:30:00 AM Lease Expires . . . . . . . : Saturday, November 05, 1998 7:30:00 AM
The name resolution method used for this sample system is Mixed (m-node) as shown by the Node Type parameter above.
Keywords: kbbug kbfix kbqfe kbhotfixserver KB176280