ypserv question

Hi
I have a very basic question regarding NIS server.
Does ypserv keep the NIS client binding information ?
TIA
-Santosh

On Tue, 19 Oct 2004 22:41:42 -0700, skwork wrote:

> Hi
> I have a very basic question regarding NIS server. Does ypserv keep the
> NIS client binding information ? TIA

No. Ypbind on the client keeps the binding information, in
/var/yp/binding. The server doesn't know what's bound to it.

The files in this directory contain a binary representation of the
server's IP address. This is not the same in other NIS implementations.
The "ypwhich" command should always be used to see what a client is bound
to.

Regards, Ian

On Tue, 19 Oct 2004 22:41:42 -0700, skwork wrote:
> I have a very basic question regarding NIS server.
> Does ypserv keep the NIS client binding information ?

No, I'm pretty sure it does not. By design NIS and NFS were designed to be
"stateless", i.e. the server does not keep any client state info. This
means that even if the server crashes (or is taken down for maintenance),
the clients can continue to work (after waiting for the server to come
back). I have done this (rebooted server, with patches, which clients run).

With NFS I think you can have "stale NFS handle" on the client side,
because it may now be using a different NFS server (depending on how
complicated your setup), but in principle the clients can always recover,
by reopening files, if necessary.

NIS is even more basic, being just a query-response kind of service. For
each query you get an immediate response, and nothing is saved/stored on
the server side. The client might cache some of that info (e.g. in nscd)
for efficiency, but not on the server side. Why should it? The data is
always available directly from the NIS database on the server. Slave
servers work the same way as the master server, except that they are
updated when the master server pushed out updates.

--
Juhan Leemet
Logicognosis, Inc.

Thanks a lot for the reply.
-Santosh

Juhan Leemet <(E-Mail Removed)> wrote in message news:<pan.2004.10.20.21.56.01.751308@logicognosis. com>...
> On Tue, 19 Oct 2004 22:41:42 -0700, skwork wrote:
> > I have a very basic question regarding NIS server.
> > Does ypserv keep the NIS client binding information ?
>
> No, I'm pretty sure it does not. By design NIS and NFS were designed to be
> "stateless", i.e. the server does not keep any client state info. This
> means that even if the server crashes (or is taken down for maintenance),
> the clients can continue to work (after waiting for the server to come
> back). I have done this (rebooted server, with patches, which clients run).
>
> With NFS I think you can have "stale NFS handle" on the client side,
> because it may now be using a different NFS server (depending on how
> complicated your setup), but in principle the clients can always recover,
> by reopening files, if necessary.
>
> NIS is even more basic, being just a query-response kind of service. For
> each query you get an immediate response, and nothing is saved/stored on
> the server side. The client might cache some of that info (e.g. in nscd)
> for efficiency, but not on the server side. Why should it? The data is
> always available directly from the NIS database on the server. Slave
> servers work the same way as the master server, except that they are
> updated when the master server pushed out updates.