Re: A very basic question

Robert Premuz (rpremuz@srce.hr)
Sat, 11 May 1996 19:20:49 +0200 (MET DST)

On Mon, 6 May 1996, Juergen Schoenwaelder wrote:

> Hi!
>
> "Bjorn J. Villa" <Bjorn.J.Villa@delab.sintef.no> wrote:
>
> > I am sorry to ask you such a childish question, but I do it anyway.
> >
> > How do I make SNMP SET operation with scotty ?
> >
> > I try: snmp# set sysDescr.0 TESTDESCR
> >
> > ......without any luck.
>
> The syntax for this command is:
>
> snmp# set varlist [callback]
>
> [etc]

Well, Juergen explained the syntax in detail. But the problem with
sending a set request by Scotty in manager role to an agent may also
be in the way the agent processes the request. (Bjorn did not say what
agent he tried to send the set request to.)

The MIB object sysDescr is described as read-only in RFC 1213, so a
proper agent should not allow you to set the sysDescr.0 variable. For
example, a Scotty in agent role doesn't allow you to set sysDescr.0
and answers with notWritable error.

The processing of set requests by a SNMP agent is quite complicated
because the set operation in an agent must support 'as if
simultaneously' behaviour.

In my graduate thesis I finished this week I implemented a kind of an
UNIX agent for Solaris 2.4/2.5. Probably, the agent is not very useful
but the actual purpose of my work was to explore the way how an SNMP
agent could be made using Scotty. (I'll write more about it in another
message, I hope).

The scotty(1) manual mentions set, check, commit and rollback SNMP
"events" for working with the set requests. But, it does not explain
in details how this events are generated, so I had to explore the
Scotty's source to discover this and to become aware that the
processing of set requests is really complicated. After all, it seems
to me that error checking in this processing is not quite in agreement
with the RFC 1905 (chapter 4.2.5.).

I noted my conclusions in the thesis but as it is written in Croatian
I should translate it to English to make it useful for broader public.

Regards.

v
-- rpr. : Robert B. Premuz
Internet: rpremuz@malik.srce.hr * Voice at home: +385 (0)1 687564