[erlang-questions] R13B and SNMP v3

[Paul Guyot]

Hello,

It seems that querying an Erlang SNMP agent using a non-Erlang manager  
with v3 protocol is broken with snmp application 4.13.1 (it does work  
with app 4.12).

The erlang system is configured as described in the tutorial on  
TrapExit (http://www.trapexit.org/SNMP_Quick_Start).
The manager is MacOS X's snmpget tool (I got similar errors with  
Net::SNMP).

[agent window]
$ erl -sname agent -config snmp/agent
Erlang R13B (erts-5.7.1) [source] [smp:2:2] [rq:2] [async-threads:0]  
[hipe] [kernel-poll:false]

Eshell V5.7.1  (abort with ^G)
(agent@REDACTED)1> application:start(crypto), application:start(snmp).
ok

[manager window]
$ snmpget -v3 -l authPriv -A "The quick brown fox jumps over the lazy  
dog." -X "Pack my box with five dozen liquor jugs." -u simple_user  
127.0.0.1:4000 1.3.6.1.2.1.1.5.0
snmpget: Unknown Report message

But if I try with R12B (snmp 4.12) :

[agent window]
$ rm -rf snmp/agent/db/*
$ sudo port deactivate erlang && sudo port activate erlang  
@R12B-5_2+smp+ssl
--->  Deactivating erlang
--->  Activating erlang @R12B-5_2+smp+ssl
$ erl -sname agent -config snmp/agent
Erlang (BEAM) emulator version 5.6.5 [source] [smp:2] [async-threads: 
0] [hipe] [kernel-poll:false]

Eshell V5.6.5  (abort with ^G)
(agent@REDACTED)1> application:start(crypto), application:start(snmp).
ok

[manager window]
$ snmpget -v3 -l authPriv -A "The quick brown fox jumps over the lazy  
dog." -X "Pack my box with five dozen liquor jugs." -u simple_user  
127.0.0.1:4000 1.3.6.1.2.1.1.5.0
SNMPv2-MIB::sysName.0 = STRING: SNMP Quick Start HowTo Demo

It seems to be related to v3 as I got it to work with v1 and v2c.
Is it related to the new discovery code that appeared with 4.13 ? If  
so, is there a way to tell the snmp application to be backward  
compatible with managers that do not understand those reports ?

Regards,

Paul