Microsoft KB Archive/98084

= LAN Manager MS-DOS NET LOGON: LANAs and Validation =

Article ID: 98084

Article Last Modified on 10/31/2006



This article was previously published under Q98084



SUMMARY
This article explains how the Net Logon command on MS-DOS LAN Manager workstations functions in relation to LANA numbers. It describes how to determine which LANA to use for a logon validation request, and explains the relative importance of validation. For more information on LANA numbers, LANA bases, and send/receive order, query on the following words in the Microsoft Knowledge Base:

LANAs and MS-DOS

The Rule
On MS-DOS LAN Manager workstations (not OS/2), logon requests are sent out ONLY on the first valid network--defined as a loaded and bound protocol driver with the lowest LANA number, which is not necessarily LANA 0. Therefore, in order to be validated during logon, a domain controller must be running the same protocol that you have loaded for your workstation's first valid network.

NET LOGON Flow
Two fundamental functions occur when you logon: validation and local name registration. The next two sections list and explain possible events that can take place within each function.

A. Validation
 The domain controller receives your logon request.

 Your account name is recognized and your password is authenticated. You will receive the message &quot;The server SERVERNAME successfully logged you on as USERID.&quot; Go to B. Your account name is recognized but your password fails authentication. The message &quot;NET3779: Your logon attempt has failed due to an incorrect username or password&quot; is displayed. Go to End. Your account name and password were recognized but your password has expired. You will be prompted to enter a new password. Go to B. The domain controller receives your request but it does not know your user ID. See step 2 below. Same symptoms; go to 2.  No domain controller receives your logon request. You receive the message &quot;You were logged on, but have not been validated by a server. Net 3778: ...&quot; Ignore the 3778 error. The important information here is that you were logged on, which really means that Step B below was completed. You were not confirmed or denied by a domain controller.</li></ol>

B. Name resgistration
Register your account name and password in your local tables. This information is used whenever you try to access a network resource. For example: When you do a NET USE you pass your user ID and password to the server, which checks the privilege level you have for that resource. This is the key security mechanism, not validation.

The only logon possibility that truly fails is 1b: account recognized but password not validated. All the others allow you to register your account and password locally on your system. This is much more important in the overall security scheme than validation.

NET LOGON Network Frames
The NET LOGON command issues frames on the LAN destined for the NETLOGON service running on a domain controller. A maximum of four mail slots addressed to \\MAILSLOT\NET\NETLOGON will be sent out to the domain. The mail slot transact Server Message Block (SMB) is sent on NetBIOS Send_Datagram frames addressed to the domain name. Which transport these travel on can vary according to protocol. For NetBEUI, the datagram is sent to the multicast address [0300000000001] that all other NetBEUI systems register as a group address. TCP/IP sends the datagram as a broadcast to the broadcast station address [FFFF FFFF FFFF hex].

There is no way to limit the number of frames sent out during validation. NET LOGON always sends a maximum of four \\MAILSLOT\NET\NETLOGON frames. When a controller responds to a request, no more attempts are submitted.

NET LOGON Miscellaneous Notes
There is no way to override the LANA used during validation. The WRKNETS parameter does not affect the NET LOGON command.

The LAN Manager server processes a validation request on all protocols it has loaded regardless of load order, LANA number, etc. SRVNETS is the only way to disable a server protocol from participating in validation.

On LAN Manager workstations, use the /DOMAIN: option to specify which domain you want to be validated in. For example: <pre class="fixed_text">NET LOGON USERID PASSWORD /DOMAIN:domain_name

Additional query words: 2.20 2.2 2.1 2.10 2.10a 2.1a 2.0

Keywords: KB98084

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