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9555269 Absent Member.
Absent Member.
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SLP vs. DNS

So I've been engaged to do some troubleshooting of issues at a client having recently completed a migration to OES from NetWare. One of the first things I notice is that there is no SLP configuration.

"Odd," says I, "Don't you NEED SLP since you have fifteen servers in three geographies with multiple subnets?"

"Nay, nay," says the client, "We are 'faking' SLP with DNS!"

How's that, you ask?

Lets say the the tree name is TREE and the O in the tree is called ORG. The servers for one location are in the container "SERVERS.SPRINGFIELD.ORG". The client seems to think that there's no need for SLP since they have a DNS zone named ORG.TREE, and DNS entries for all the servers (like "HOST1.SERVERS.SPRINGFIELD.ORG.TREE").

While the resolution works, and they've got SLP disabled in the "Protocol Preferences" of the Novell Client, I posit that this doesn't eliminate the need for SLP.

I won't sully the conversation with my opinions. I'm curious though, is the logic reasonable? Or is this client full of beans?
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4 Replies
Knowledge Partner
Knowledge Partner

Re: SLP vs. DNS

Hi,

9555269 wrote:
>
> "Nay, nay," says the client, "We are 'faking' SLP with DNS!"
>
> How's that, you ask?


Stupid. 😉

> Lets say the the tree name is TREE and the O in the tree is called ORG.
> The servers for one location are in the container
> "SERVERS.SPRINGFIELD.ORG". The client seems to think that there's no
> need for SLP since they have a DNS zone named ORG.TREE, and DNS entries
> for all the servers (like "HOST1.SERVERS.SPRINGFIELD.ORG.TREE").


You can use DNS of course to find an IP for an already known name.
Including tree and server names. What DNS of course can *not* do, is
deliver any type of service, nor can it be used to browse existing
services. With SLP, any service aware of it can go ahead and ask for a
list of al known NCP servers, or all existing partitions of a given eDir
replica. Nothing like this is possible with DNS. The most obvious place
where you can see the difference is i nNetwork Neighborhood. Without
SLP, the "Netware Servers" list underneath is empty, except servers you
have already logged into.

Not to mention of course that DNS is static, human configured, and as
such prone to errors.

> While the resolution works, and they've got SLP disabled in the
> "Protocol Preferences" of the Novell Client, I posit that this doesn't
> eliminate the need for SLP.
>
> I won't sully the conversation with my opinions. I'm curious though,
> is the logic reasonable? Or is this client full of beans?


DNS is a potential fallback option in case SLP has a problem. Relying on
DNS exclusiely for name resolution is needlessly making life
complicated, and asking for trouble.

CU,
--
Massimo Rosen
Novell Product Support Forum Sysop
No emails please!
http://www.cfc-it.de
CU,
--
Massimo Rosen
Micro Focus Knowledge Partner
No emails please!
http://www.cfc-it.de
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Knowledge Partner
Knowledge Partner

Re: SLP vs. DNS

It almost sounds like they're used to an AD environment where MS practically forces you to use Dynamic DNS.

In that case, (for AD purposes) it works, although a bit chatty for my taste and I don't like client pc's registering themselves via dynamic dns, but if you're a Windows shop you don't really have much of a choice anymore.
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Marcel_Cox Absent Member.
Absent Member.

Re: SLP vs. DNS

Technically, MS does the same with DNS that Novell does with SLP. Services
register with DNS through service records and workstations can then find
the services by reading these service records. However because Novell does
not use service records in DNS, DNS is not a full replacement for SLP in a
Novell environment and SLP is really needed if you want to benefit from
services dynmically making themselves known.

--
Marcel Cox
http://support.novell.com/forums
------------------------------------------------------------------------
Marcel Cox's Profile: http://forums.novell.com/member.php?userid=8
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Knowledge Partner
Knowledge Partner

Re: SLP vs. DNS

Thanks Marcel. I'm not an AD guru by any stretch. Personally I've had far less problems with DNS than with SLP (I guess we're just really careful about not putting "bad" things in DNS). In terms of locating "things" that is. (caching has been a problem with both at times, but it is what it is).
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