Different encoding of results

[stuarthannig]

Using gem 'netsnmp', '~> 0.3.0'

Is this an issue with xor? I installed xorcist, but same results.

This is the request/results from the snmpwalk command on CLI:

$ snmpwalk -v 3 <auth> <ip address> 1.3.6.1.4.1.1991.1.1.3.33.1.1.1.4

iso.3.6.1.4.1.1991.1.1.3.33.1.1.1.4.8.76.65.71.45.77.65.84.72 = Hex-STRING: 00 00 00 06 00 00 00 07 00 00 0C 8C
iso.3.6.1.4.1.1991.1.1.3.33.1.1.1.4.14.76.65.71.45.84.72.69.45.84.72.73.78.71.83 = Hex-STRING: 00 00 00 0A 00 00 00 0B 00 00 0C 0A
iso.3.6.1.4.1.1991.1.1.3.33.1.1.1.4.14.76.65.71.45.84.72.69.83.69.45.65.76.83.79 = Hex-STRING: 00 00 00 10 00 00 00 11 00 00 0C 88

This is the results from this gem, converted to hash from the Enumarato (for readability):

=> {
  "1.3.6.1.4.1.1991.1.1.3.33.1.1.1.4.8.76.65.71.45.77.65.84.72"=>
  "00 00 00 06 00 00 00 07 00 00 0C 8C",
 "1.3.6.1.4.1.1991.1.1.3.33.1.1.1.4.14.76.65.71.45.84.72.69.45.84.72.73.78.71.83"=>
  "\u0000\u0000\u0000\n\u0000\u0000\u0000\v\u0000\u0000\f\n",
 "1.3.6.1.4.1.1991.1.1.3.33.1.1.1.4.14.76.65.71.45.84.72.69.83.69.45.65.76.83.79"=>
  "00 00 00 10 00 00 00 11 00 00 0C 88"
  }

The first and last values are <Encoding:US-ASCII>, but the second value is <Encoding:UTF-8>. Is it possible to force the encoding to the ASCII encoding? As we can see from the returned values, ASCII matches the results from the CLI.

Having two different encodings requires a conditional to handle the results separately.

[HoneyryderChuck]

Hi @stuarthannig thank you for the report.

I think it might have smth to do with this: https://github.com/swisscom/ruby-netsnmp/blob/master/lib/netsnmp/varbind.rb#L51

My question here would be, how could you distinguish between the string and hex string, if not using this admittedly naive approach?

I'd suggest you set a breakpoint here and check what causes the middle value to be convertible, and how else could you identify it as an hex string

[HoneyryderChuck]

https://stackoverflow.com/questions/35439244/how-to-convert-the-hex-value-that-i-receive-from-snmp for reference.

The netsnmp cli tool uses MIB information about the OID to know how to parse it.

Given that now there's a MIB parser, one could take advantage of this.