On Sat, May 09, 2009 at 08:48:12AM +0000, Grant Edwards wrote: [snip]
> What I'd like a pointer on is the interface numbering in SNMP > OIDs. Are the interfaces supposed to be numbered 1..N with > interface 0 being non-existent? Or are eCos interface numbers > off by one and they should really be 0,1 instead of 1,2? [I > tried looking through the OID/ASN.1 docs, but got lost rather > quickly.] > > If SNMP interface numbers are supposed to start at #1, why do > HP and Cisco SNMP managers ask for attributes of interface #0? > Not only those Network managers... Any hacker can hang a "stupid" device then I tried it on my ADSL modem snmpwalk -c public -v1 bridge.local IF-MIB::ifPhysAddress.0 IF-MIB::ifPhysAddress.0: Unknown Object Identifier (Index out of range: 0 (ifIndex)) But it still ping itself :-) > I looked at network traces for one customer site using, I > believe, HP Insight. It does read the interface attributes for > interfaces 1 and 2. I don't see it attempt to read attributes > for interface 3 (which doesn't exist). I do see it attempt to > read attributes for interface 0 (which also doesn't exist). > > If interface numbers are supposed to start at #0, will > renumbering the interfaces at this point (after product has > been shipping for 7 years) cause more problems that it will > solve? That's known SNMP "issue" -- “get” might want that the OID ends in .0 Example: snmpget -c public -O X -v2c bridge.local sysDescr SNMPv2-MIB::sysDescr = No Such Instance currently exists at this OID snmpget -c public -O X -v2c bridge.local sysDescr.0 SNMPv2-MIB::sysDescr.0 = STRING: Foo bar baz So, IMHO, it's better to fix the agent than to make managers work "properly". Sergei -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
