[mrtg] Can not determine ifNumber for public at gw

[Steve Shipway]

> IF-MIB::ifDescr.0 = STRING: ppp0
...
> IF-MIB::ifDescr.15 = STRING: ppp0
> IF-MIB::ifDescr.16 = STRING: ppp0
> IF-MIB::ifDescr.17 = STRING: ppp0
> ...
> IF-MIB::ifDescr.83 = STRING: ppp0
> IF-MIB::ifDescr.84 = STRING: ppp0
> IF-MIB::ifDescr.85 = STRING: ppp0
> IF-MIB::ifType.0 = INTEGER: ppp(23)
...
> IF-MIB::ifType.15 = INTEGER: ppp(23)
> IF-MIB::ifType.16 = INTEGER: ppp(23)
> IF-MIB::ifType.17 = INTEGER: ppp(23)
> ...
> IF-MIB::ifType.83 = INTEGER: ppp(23)
> IF-MIB::ifType.84 = INTEGER: ppp(23)
> IF-MIB::ifType.85 = INTEGER: ppp(23)
... 
> Probably way more than you needed to see, but it should be abundantly
> clear that all of the up/down of ppp0 has resulted in lots of
> interfaces being enumerated with the current active ppp0 being on index
> 85.
> 
> Is there something about this that mrtg doesn't like?

Yes.  MRTG has no way to uniquely identify which interface you want to graph.  Many are called 'ppp0', many have type 23, the ppp interfaces have no MAC address, and so on.

This is a very odd state of affairs with multiple interfaces with the same name; also it appears the only 'up' interface is the last (number 85) so I assume this changes.

You might like to review your ppp start/stop code as it seems to be creating a new interface ppp0 every time it restarts rather than closing down the old one, or something?  I suspect a reboot will leave you with a single ppp0 interface again (after which it will work) but then the next restart of the interface might start spawning more copies...

Steve