[erlang-bugs] IPv6 problems in erlang's SNMP stack

[Raimo Niskanen]

I just would like to inform you all that in the upcoming 17.2
OTP patch release we are starting to fix snmp for IPv6.  The
agent should be able to handle IPv4+IPv6, but the manager
just IPv4 or IPv6.

The documentation is not updated, though...  And the code
for creating configurations is not fully updated.

Dual stack manager is in the pipeline.  The new code is supposed
to be backwards compatible unless you have written a custom
net_if process.  And of course there might be bugs.

Best regards
/ Raimo Niskanen



On Fri, Jan 24, 2014 at 11:10:55AM +0100, Stefan Zegenhagen wrote:
> Dear all,
> 
> 
> First problem: I found no easy way to pass the "inet6" socket option
> into erlang's snmpa_net_if implementation to open the UDP socket in IPv6
> mode. Such an option would be required to convince erlang's SNMP stack
> to talk IPv6.
> 
> Second problem: when a socket is opened in IPv6 mode on real dual-stack
> operating systems, it is possible to query the SNMP agent via IPv4 *AND*
> IPv6 simultaneously. Sending traps to IPv6 trap receivers works as well,
> but trap receivers that are configured with IPv4 addresses always fail
> with an eafnosupport error. SNMP-TARGET-MIB explicitly allows trap
> receivers to have different IP address types, so I would expect such a
> feature to be supported.
> 
> I know that it is possible (the Linux kernel sends out IPv6 packets
> addressed to "::FFFF:A.B.C.D" via IPv4). I also know that there is a
> portability problem, since operating systems may behave differently when
> it comes to dual-stack operation details (its probably best being fixed
> in the socket driver). Still, this is an important issue for us at the
> moment and I guess others will face the same problem when IPv6 spreads
> wider.
> 
> 
> Kind regards,
> 
> -- 
> Dr. Stefan Zegenhagen
> 
> arcutronix GmbH
> Garbsener Landstr. 10
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-- 

/ Raimo Niskanen, Erlang/OTP, Ericsson AB