Which SLP option?

Christian Voelker wrote:

> So which option should I use? For the first server and for all the other?
>
> If I disable OpenSLP, does eDirectory serve any SLP-feautures?
>
> For our needs we don't use SLP, but I think, eDirectory uses it.
>
> So what to do? Is there an good link to this "problem" of the OES?

I'm by no means any sort of authority on this, I'm very new to it myself
and still learning lots each day, but I'll say what I know as nobody
else has commented:

I recently did the 3017 eDirectory Fundamentals training.

In the book it talks about how Netware used to locate services via IPX
using SAP (Service Advertisement Protocol) and how SLP was developed to
achieve the same thing on IP only networks.

SAP supposedly advertised a service on the network by regularly
broadcasting "I'm this service and I'm ready and you can find me on this
address" for example. This didn't scale well on large networks as there
was a lot traffic, often for services that were never used or needed.

So SLP came along, and without it, you would not be able to login to a
tree with something like Novell client without knowing the IP address or
DNS name of the master server of the tree or a server holding a replica.

An SLP Service Agent (SA) running on a server registers the available
services of that server with a Directory Agent (DA). The DA acts as a
central repository for available services. A User Agent (UA) is
something like the Novell Client that requests information on behalf of
an application from a DA.

All these agents can locate each other through IP/DNS, DHCP or
multicast. As the install points out, too many servers in a multicast
setup generates too much traffic as is best avoided.

There is also the concept of scopes, to group services, and each scope
can have its own DA, which you could use to geographically isolate
service groups or simply to spread SLP load/traffic.

By default only UAs and SAs are setup and they use Multicast, as you've
noted in the install, you can either use multicast or not use it at all.

You can check if multicast is enabled with 'netstat -nr' - if you see
something about 224.0.0.0 it is enabled, if it is not you can do:

route add -net 224.0.0.0 netmask 244.0.0.0 dev {interface such as eth0}

This will get things running via UAs and SAs and will service a small
install of servers.

The default install of eDirectory is said to come with an slpuasa daemon
which is not capable of being a DA, so OES installs OpenSLP to allow this.

If you are using more the a couple of servers, do not enable multicast
and do things with a DA.

You need to setup your first DA manually, and then all subsequent
servers you can tell to use an existing server. It would be nice for
the OES install to offer this step for you - luck I did the course or
I'd never have figured it out :)

/etc/slp.conf is the config file

You should generally only have to do the following:

uncomment the 'net.slp.useScopes' line and put a new scope name of your
choosing, such as:

net.slp.useScopes = eDirScope

uncomment the 'net.slp.DAAddress' line and enter the IP of that server,
this allows local SAs and UAs to use the DA you are setting up on that
server, so it can do self-lookups essentially:

net.slp.DAAddress = 10.0.0.1

uncomment and set 'net.slp.isDA' to true:

net.slp.isDA = true

You should then be able to '/etc/init.d/slpd start' - also check your
runlevel configs for this service to ensure it starts on boot - I think
it does by default.

You can then use the slptool command to see if things are working.

Subsequent servers should be told to use (in this example) the 10.0.0.1
server and the eDirScope scope when you do the OES SLP config during the
install. You can use the slptool command on again on the DA server to
see if services from the new server are being registered correctly. It
normally registers LDAP and SSH services at the very least, one of my
setups looks like this:

v20z-1:~ # slptool findscopes
eDirScope

v20z-1:~ # slptool findsrvtypes
service:ntp
service:ssh
service:fish
service:remotedesktop.kde:vnc
service:remotedesktop.java:http
service:smb
service:bindery.novell
service:ndap.novell
service:ldap

v20z-1:~ # slptool findsrvs service:ldap
service:ldap:///10.2.10.1:389.,3540
service:ldap:///10.2.10.8:389.,3555

This shows that 2 servers are registered as offering an LDAP server, the
DA itseld (10.2.10.1) and 10.2.10.8

I hope that helps, and I hope there isn't too much mis-information in
there - please correct me if there is :)

Regards,

Ryan