[HamWAN PSDR] SNMP Assistance Requested: The Surprising Solution

Herb Weiner herbw at wiskit.com
Fri Feb 28 08:08:06 PST 2020

Not sure whether this is a bug or an (undocumented) feature, but when /interface wireless scan 0 is running, the device returns bogus values for some OIDs and completely omits other OIDs.

The solution: Do NOT run /interface wireless scan 0 if you intend to query the device using SNMP.


> On Feb 23, 2020, at 3:46 PM, Herb Weiner <herbw at wiskit.com> wrote:
> Thanks, Bart.
> I had already reviewed that document (last updated "201912100000Z"), and it unfortunately was not very helpful. I had also already used snmpwalk to explore all of the available OIDs in the Mikrotik MIB. That also wasn't very helpful. Note that I am using the most recent firmware, version 6.46.3. For example:
> strength (., the value that I am most interested in, is documented in the Mikrotik MIB (MIKROTIK-MIB::mtxrWlStatStrength.1) as a 32 bit integer. The only description provided is "dBm". Based upon the OID name and the description, the best assumption I could make was that this would be the received signal strength on the wireless interface. But this variable always returns the value 1, whether or not the wireless interface is receiving a signal at all.
> The Mikrotik MIB documents an OID MIKROTIK-MIB::mtxrWlRtabRadioName, a Display String concisely described as "". (That's right. You have to guess what it is.) I was hoping that this would correspond to the RADIO-NAME shown by the /interface wireless scan 0 command. But neither snmpget nor snmpwalk can even find this OID. Although it is documented, it apparently does not exist on my LHG XL HP5.
> Some of the information that I'm looking for may actually be available, but because the Mikrotik MIB is so poorly documented, I may not realize that any given OID may be exactly what I'm looking for.
> Since I have already spent many hours investigating this, I was hoping that someone with some practical experience could provide some suggestions.
> Herb
>> On Feb 22, 2020, at 9:44 PM, Bart Kus <me at bartk.us <mailto:me at bartk.us>> wrote:
>> RouterOS supports the following MIBs:
>> https://wiki.mikrotik.com/wiki/Manual:SNMP#Management_information_base_.28MIB.29 <https://wiki.mikrotik.com/wiki/Manual:SNMP#Management_information_base_.28MIB.29>
>> --Bart
>> On 2/22/2020 4:59 PM, Herb Weiner wrote:
>>> I would like to use SNMP to facilitate aiming a Node. In order to work on this project, I have setup a Node (LHG XL HP5) and Sector (5SHPn) for testing purposes.
>>> The following shows the status of my Node:
>>> [herbw at AA7HW-01] > /snmp print 
>>>           enabled: yes
>>>           contact: #HamWAN-Support on irc.freenode.org <http://irc.freenode.org/>
>>>          location: 45.489139,-122.631972
>>>         engine-id: 
>>>       trap-target: 
>>>    trap-community: hamwan
>>>      trap-version: 1
>>>   trap-generators: temp-exception
>>> [herbw at AA7HW-01] > /interface wireless print oid
>>>  0 tx-rate=. 
>>>    rx-rate=. 
>>>    strength=. 
>>>    ssid=. 
>>>    bssid=. 
>>>    frequency=. 
>>>    band=. 
>>>    auth-client-count=. 
>>>  [herbw at AA7HW-01] > /interface wireless scan 0
>>> Flags: A - active, P - privacy, R - routeros-network, N - nstreme, T - tdma, W - wds, B - bridge 
>>>        ADDRESS           SSID          CHANNEL        SIG   NF SNR RADIO-NAME        ROUTEROS-VERSION       
>>> A RT B 4C:5E:0C:89:3F:57 HamWAN        5880/5/an      -28 -124  96 K7ICY-Tolliver   
>>> -- [Q quit|D dump|C-z pause]
>>> Based upon the above, I would assume that if I query the signal strength (. using snmpget, I would obtain a value of approximately -28 (the signal strength varies a bit from the instantaneous value of -28 reported above). However, although I am able to obtain the SSID using snmpget, I am unable to obtain the signal strength, frequency or band:
>>> $ snmpget -c hamwan .
>>> SNMPv2-SMI::enterprises.14988. = INTEGER: 1
>>> $ $ snmpget -c hamwan .
>>> SNMPv2-SMI::enterprises.14988. = STRING: "HamWAN"
>>> $ snmpget -c hamwan .
>>> SNMPv2-SMI::enterprises.14988. = INTEGER: 0
>>> $ snmpget -c hamwan . 
>>> SNMPv2-SMI::enterprises.14988. = ""
>>> $ 
>>> Also, is it possible to obtain the Noise Floor (NF), Signal to Noise Ratio (SNR), or Radio Name from my Node using SNMP? These are all reported by the /interface wireless scan 0.
>>> Thanks for any assistance you can provide.
>>> Herb, AA7HW
>>> _______________________________________________
>>> PSDR mailing list
>>> PSDR at hamwan.org <mailto:PSDR at hamwan.org>
>>> http://mail.hamwan.net/mailman/listinfo/psdr <http://mail.hamwan.net/mailman/listinfo/psdr>

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