SNMP - issues to resolve before making a release

Micael Karlberg <>
Fri May 12 12:59:21 CEST 2006


Hi,

karol skocik wrote:
 > Hi,
 >  we are before making a first release of our application, with SNMP
 > agent bundled in. Now, when I look into SNMP after some time spent on
 > working with Erlang SNMP lib, 3 issues comes to my mind, which are
 > quite important for me to know, before I tell my boss that evrything
 > works ok.
 >
 > 1. First, we have SNMP agent v3, with authentication and privacy, and
 > this means dependence on crypto library. However, SNMP app file does
 > not mention anything about crypto, and that's why it is needed to
 > explicitly write crypto into rel file, which is far from normal Erlang
 > elegancy. Is there any reason why it is so, or it is a "feature" ;)
 > ?? Is there any way to fix it?

The dependency of the crypto application exist only if you configure
the agent to use v3! There is a comment about this in the snmp app-
file. There is no way I know of to specify a conditional dependency.

Maybe it should be made more clear in the SNMP documentation, that
this has to be taken care of by the user of the SNMP application
toolkit.

 >
 > 2. When I have changed something in configuration which looks like this :
 >
 > [{snmp, [{agent,
 >          [{db_dir, "/var/lib/ipe"},
 >           {config, [{dir, "/etc/ipe"}]},
 >           {net_if, [{options, [{bind_to, false}]}]}]}]},
 > {mnesia, [{dir, "/var/lib/ipe"}]},
 > {yaws, [{embedded, true},
 >         {logdir, "/var/log/ipe"},
 >         {docroot, "/var/www/ipe"},
 >         {include_dir, ["/var/www/ipe"]},
 >         {listen, {0, 0, 0, 0}}]}
 > ].
 >
 > the change took always effect after restart, no matter that force_load
 > is false by default, and this means it should take config from
 > database - ignoring what is written in config file. Do I understand it
 > well?
 >  In this context - what is the purpose of database in agent -
 > especially config database? Why not just load config from conf files +
 > config file?

Do you meaning the SNMP agent config file(s) (agent.conf, context.conf,
standard.conf, ...) located in "/etc/ipe" (in your case)? Because if
you do, the configuration is not just read but also processed, and it
may take awhile to load everything, especially all the MIBs.

If the mean the config you specified above (the system configuration
file), then this is read only when starting and appgrade. But, in any
case the snmp agent will only read this stuff when it starts.

 >
 > 3. Last but not least - when we change the machine address with our
 > product with SNMP agent, do we need to fix the intAgentIpAddress in
 > agent.conf to continue functioning?

Read abot the bind_to config option in chapter "Running the application"
of the User's Guide.
You can ofcourse always write your own net_if module (this is supported
by the agent, as long as you follow the API specification).

 >
 > Karol
 >
 >

Regards,
	/BMK





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