Configuring SLP with an UNSCOPED directory agent (DA)
(Last modified: 15Nov2005)
This document (10060296) is provided subject to the disclaimer at the end of this document.
Configuring SLP with an UNSCOPED directory agent (DA)
Novell NetWare 5.1 Support Pack 3 (NW51SP3.EXE)
Novell NetWare 5.1 Support Pack 4 (NW51SP4.EXE)
Novell NetWare 5.1 Support Pack 5
Novell Service Location Protocol (SLP) v1
Novell SLP Directory Agent (SLPDA.NLM)
SLP is not working
IP communication is not working
Workstations cannot browse the network
Servers and workstations can ping each other
Servers cannot communicate with each other
For configuration of a SCOPED DA, please see TID# 10059981 (NOVL38370)
For Additional SLP Design and Implementation Guidelines, please see TID# 10062474 (NOVL48348)
Additional documentation can be found at: http://www.novell.com/documentation/lg/ndsedir/docui/index.html#../taoenu/data/a5eyqkl.html
SLP does for IP what SAP does for IPX. SLP, in the default configuration, uses multicast to discover IP services on the network. This works very well in non-routed environments. If using a router that blocks these multicasts, or in a very large routed environment, SLP needs to be configured to use unicast instead of multicast. This requires the use of an SLP directory agent (DA).
The DA acts as a directory of IP services on a network (much like a phone book of the network). As a server's IP services become available, the server contacts the DA and informs it of the existence of these new services (the services are registered with the DA, almost like placing phone numbers in the phone book). When the services are halted, the server again notifies the DA. Whenever a server or workstation wants to find a service, it asks the DA for the information.
SLP is intended for use with NetWare versions 5.0 and higher. There is no need to configure lower versions of NetWare when following these instructions.
Here are the steps to configure SLP to use unicast:
1) Select a server to act as a DA. This server needs to have NetWare version 5.0 or higher. All of the other servers and all of the workstations will need to contact it, so choose one in a central location if possible. The server must have a master or read/write replica of its own container. This will allow faster access to the DA. It is okay to have two DA's for fault tolerance. Please see the note at the bottom of this document for more information.
2) If SLPDA.NLM is loaded on any server, unload it. Make sure that no servers, including the DA server, have a line in the AUTOEXEC.NCF file that loads SLPDA.NLM.
3) Search the directory tree for objects of type "SLP Directory Agent" and "SLP Scope Unit." Delete them. This will clear out any previous attempts at setting up directory agents. It may be necessary to delete the contents of the scope units before deleting the units themselves. If unable to delete these objects, verify that SLPDA.NLM is not running on any server and try again. If still unable to delete them, use ConsoleOne instead of NWADMIN32 for this step.
4) Edit SYS:\ETC\SLP.CFG on the DA server and make sure that there is nothing in this file besides comments.
5) Edit SYS:\ETC\SLP.CFG on all of the other servers (not the DA server) and add a line that says, "DA IPV4, XX.XX.XX.XX" (without the quotes and where "XX.XX.XX.XX" is the IP address of the DA). Make sure that there are no other lines in this file except for the comments. It might be convenient to edit this file on one server and then copy it to the others. If this step is not done, the servers may not be able to communicate with each other.
6) Add a line to the AUTOEXEC.NCF file on the DA server that loads SLPDA.NLM. This line can go at the end of the file.
7) Load SLPDA.NLM on the DA server. CHOOSE YES FOR THE AUTOMATIC CONFIGURATION.
8) Type "SET SLP RESET = ON" at the DA server's console.
9) Type "DISPLAY SLPDA" at the DA server's console. A line appears that starts with "SLP LOOPBACK ADDRESS : ACTIVE :" followed by the scope name. (There should be no other lines unless using more than one DA.)
10) Type "SET SLP RESET = ON" at the console of all of the other servers.
11) Type "DISPLAY SLPDA" at the consoles of the OTHER servers. A line appears that starts with "XX.XX.XX.XX : ACTIVE : " (where XX.XX.XX.XX is the IP address of the DA server) followed by the scope name.
12) Configure the workstations, either manually (Novell client properties on the "Service Location" tab) or using NetWare DHCP (option 78), with the IP address of the DA. If doing this via DHCP, set 'mandatory' if the desired effect is to have DHCP actually override any local settings. Unload DHCPSRVR and load it again for the DHCP Server to hand out this information. The workstations also need to be restarted to make the change effective. If this step is not done, the workstations may not be able to communicate with the servers.
NOTE: It is possible to configure multiple DA's, but in most cases it is not recommended. Multiple DA's are used primarily for redundancy, but in some special cases they can be strategically placed to provide a performance enhancement. However these instances have proven to be rare. Make sure that the DA's meet the following requirements: 1) They should be in the same physical location (not crossing a WAN link) when possible, but in SOME cases placing a DA across the WAN is acceptable and will work just fine (Keeping in mind that NDS replication and communication can be significantly affected). 2) they must both have master or read/write replicas of the partition that contains the scope unit (once again, there have been instances where both servers did NOT have a replica and still functioned, but this is not the norm, and is not recommended by Novell). It is recommended to create an OU in which to place the scope unit and partition that OU off, giving the DA servers replicas of this partition. It is also recommended to limit the number of DA's to between 2-4 depending on the size of the network and DA placement.
The configuration process for multiple DA's is slightly different than when configuring only one DA. The first DA in the tree is configured as stated in the above instructions. The the other DA's are configured differently. To configure more DA's do the following:
1) Highlight the desired context for the DA to reside in. (ex..the O or OU for the DA)
2) Click the create button on toolbar
3) Select SLP Directory Agent
5) Highlight the DA object
6) Right click
7) Select details and enter (the Configuration screen appears)
8) Click the Browse button by Host Server
9) Browse to the server that will host the DA
10) Click the SLP Scope Units tab (the SLP Scope units screen appears)
11) Click the add button and Browse to the Scope object named UNSCOPED
12) Select the scope and click OK (the scope should appear in the Serviced scope units box)
13) Click OK to complete the SLP configuration
14) At the server console of the second DA
a) Load SLPDA (this time it should not ask to accept any defaults it should just load ' this activates the DA on that Server)
15) Add the second DAs IP address to the Directory Agent list in the clients and the SLP.CFG file of all the other servers.
All of the workstations should have the IP addresses of both DA's added to their directory agent list. All of the non-DA servers should have two lines added to the SLP.CFG file (one for each DA). It is recommended that the DA servers have each other's IP address in their SLP.CFG files. (i.e. Server A will have server B's IP address in its file, server B will have server A's IP address in its file, but neither DA server will have its own IP address in its own SLP.CFG file.) If a DA server has its own IP address in its SLP.CFG file, it won't work right.
WARNING: THESE INSTRUCTIONS ARE VALID ONLY FOR CONFIGURING SLP WITH THE USE OF THE DEFAULT SCOPE "UNSCOPED". WHEN USING THE DEFAULT SCOPE "UNSCOPED" THERE CAN BE ONLY ONE SCOPE OBJECT IN THE TREE. USE OF THE UNSCOPED SCOPE WITH MORE THAN ONE SCOPE OBJECT IN THE TREE WILL CAUSE NETWORK COMMUNICATION PROBLEMS!.
|Document Title:||Configuring SLP with an UNSCOPED directory agent (DA)|
|Novell Product Class:||Connectivity Products|
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