[AGENT++] Trap destinations

[michael.carr at bt.com]

Thanks Frank, a load more questions though...

What exactly does "allow_agentx_tcp_from_localhost" do?  Does it mean
that all communication between the subagent and master is via TCP as
opposed to UDP?  (Can it be that simple to get SNMP via TCP?!)  Can I
remove the call without affecting the master/subagent?  With v3 still
enabled and removing the call it appears to have no effect on our target
Linux but causes the master to assert and so crash on Windows when the
subagent runs up.

With v3 disabled which of the "standard" MIBs are really needed?  I'm
still trying to get to as small a foot print size as possible.  It looks
as though the snmp_target_mib, snmp_notification_mib & sysGroup calls
are the only ones I need, is that correct?  Or are the other ones,
snmpGroup and TestAndIncr(oidSnmpSetSerialNo), required for things to
function correctly?  The first definitely looks like I don't need it but
the second I'm unsure on.  I can just comment them out and try but I'd
like to get confirmation of sorts that it won't cause a problem further
down the line.

With v3 disabled it also disables the trap class in the code generated
by AgenPro 2, is this correct or an error?  If not an error why dose it
get disabled?  It seems odd for it to do that especially since I can
remove the #ifdef'd around the trap class and it works ok.  Again, this
may be a false lead and problems may surface further down the line?

Thanks,
Mike


-----Original Message-----
From: Frank Fock [mailto:fock at agentpp.com] 
Sent: Monday, May 14, 2007 10:09 PM
To: Carr,M,Michael,JGFTY C
Cc: agentpp at agentpp.org
Subject: Re: [AGENT++] Trap destinations

Hi Mike,

michael.carr at bt.com wrote:
> 
> If I disabled v3 support (in order to reduce the footprint size - see 
> my other thread/email) are SNMP-TARGET-MIB and SNMP-NOTIFICATION-MIB 
> still used to set the trap destinations?  I was under the impression 
> these MIBs were added as part of v3 but going on the example master 
> code they're not excluded from a build when v3 is disabled.
>
Both MIB modules can be used for SNMPv1/v2c too and they provide a
standardized way to configure trap targets. That's why those modules are
not excluded when _SNMPv3 is not defined.

> If indeed SNMP-TARGET-MIB and SNMP-NOTIFICATION-MIB were introduced by

> v3, what mechanism for trap destinations did v1 & v2 use prior to v3?

Before those MIB modules have been specified, each vendor used its own
proprietary mechanisms.

> This is probably a really basic question but I'm still learning about 
> SNMP etc. so you'll have to bare with me :)
> 
> Also, what is the purpose of the call to 
> "allow_agentx_tcp_from_localhost();"?  The comment before the call has

> me puzzled since it gets disabled when v3 is disabled - unless the 
> comment is referring to the VACM entries?
> 
Mmmh, it seems the enclosing #ifdef is a relict. Some time ago, the
SNMP-COMMUNITY-MIB where only supported when _SNMPv3 was defined. This
is no longer the case and thus the #ifdef can be removed.

Best regards,
Frank