Interpreting Hex Values for SNMP

  • Thread starter Thread starter Derill03
  • Start date Start date
Click For Summary

Discussion Overview

The discussion revolves around interpreting a table of hex values related to SNMP (Simple Network Management Protocol). Participants are attempting to decode specific fields such as the community string, PDU type, OID, and the contents of the OID location from a hex dump, with a focus on understanding the structure and meaning of the data presented.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant seeks help in interpreting hex values for SNMP, specifically identifying the community, PDU type, OID, and contents of the OID location.
  • Another participant suggests using online tools like SNMPwalk and Wireshark for analysis, while one participant notes that they cannot use utilities for classwork.
  • One participant claims to have identified the community as "private" and the PDU type as "response," but expresses uncertainty about the contents of the OID location.
  • Another participant questions how the community was deduced as "private" and seeks clarification on the hex values corresponding to the community field.
  • There is a discussion about the significance of the hex values, with one participant suggesting that the community is "public" based on the length of the ASCII characters.
  • Participants debate the correct interpretation of the OID value, with one suggesting it is 1.3.6.1.2.1.1.5.0, while another expresses confusion about the remaining values in the data string.
  • Clarifications are made regarding the identification of the OID, with one participant stating that the OID is indicated by the hex values 06 followed by its length.

Areas of Agreement / Disagreement

Participants express differing interpretations of the community string and the OID value, leading to unresolved questions about the correct decoding of the hex values. There is no consensus on the exact meanings of the values presented.

Contextual Notes

Participants rely on their interpretations of hex values and examples from external resources, but there is uncertainty regarding the exact definitions and representations of the community and OID values. The discussion reflects varying levels of understanding and assumptions about the SNMP protocol.

Derill03
Messages
62
Reaction score
0
Can anyone offer any assistance with interpreting a table of hex values for SNMP? I know the column on left is the memory locations and the first 10 bytes are the ethernet header but i can not find any resources that show how to interpret the hex dump.

I need to identify:

Community
PDU type
OID
Contents of OID location

0020 00 7d 00 a1 d3 a5 00 3b d9 39 30 31 02 01 00 04
0030 06 70 75 62 6c 69 63 a2 24 02 04 66 6a 7f 7b 02
0040 01 00 02 01 00 30 16 30 14 06 08 2b 06 01 02 01
0050 01 05 00 04 08 48 50 4c 4a 32 32 30 30
 
Computer science news on Phys.org
Try wireshark, which I recommend to analyze any network traffic or troubleshoot any network problems.
http://www.wireshark.org/
 
This is for classwork i can not use any utilities
 
Here's one:
http://www.rane.com/swf/n161fig5.swf
 
Ok i think I've figured some out:

community = private
PDU type = response
and i think OID value is: 1.3.6.22.48.20.6.8.43.6.1.2.1.1



I don't know what it means by "contents of the OID location"?
 
Hmm, at which address did you find the community?
And how did you deduce it was private?
 
from the link you gave me i have been kind of trying to match up values and what they mean, and i think I've deduced that A4 is the PDU type = response, and the 04 is where i got the community from. I can't find anything about values for the community field so in my string i see a 04 in about same location as the figure i have.

The OID value i posted has to be wrong actually i think it is 1.3.6.1.2.1.1.5.0.4 because the string near end 06 08 2b 06 01 02 01 01 05 00 04 i think is telling me the value is 8 octets in length starting at 06
 
Umm... the picture I linked to is an example.
It shows how "private" would be encoded for the community.
But your hex dump has a different community...
It starts with 04 signifying the start of the community.
It is followed by 06 indicating 6 bytes length ("private" is 7 bytes).

And where did you find A4?
I don't see it.

Btw, here's the page that contains the picture:
http://www.rane.com/note161.html
 
Last edited:
  • #10
sorry i meant A2 = response for PDU in the 0030 row

Is there anywhere i can find a table or listing of how to tell what the community is for different byte lengths? I have searched and i am coming up empty handed that's why i came here for some extra help.

So from what your saying 04 represents the start of the community and the following value tells how many bytes the community is
 
  • #11
Wait is the community "Public" because public is 6 ascii characters and private is 7 so it makes sense?
 
  • #12
no its public because the 6 characters that follow are ascii for "public" ok i know that is correct.

Can you help me understand the OID value some more, i know it starts at 06 08 2b going from my educated guess way of thinking i think it is 1.3.6.1.2.1.1.5.0.4 but to be honest it don't make sense because i still have so many values left but the only connection i can make is that in the example you gave me the value after 06 was 0d and there was 13 values left in the data string
 

Similar threads

  • · Replies 58 ·
2
Replies
58
Views
5K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 6 ·
Replies
6
Views
5K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 11 ·
Replies
11
Views
6K
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
6K
Replies
6
Views
5K
  • · Replies 23 ·
Replies
23
Views
6K