From Net-SNMP Wiki

Why can't I see values in the <INSERT ENTERPRISE HERE> tree?

If you're walking a specific tree, but failing to see anything in it, then the most likely cause is that the agent simply does not implement those particular MIB objects. Or if it does, that the access control or other configuration settings mean that there's nothing for you to see there.

However, if you're trying a basic 'snmpwalk' with no explicit OID specified, then this would also explain why you're not seeing any enterprise-specific results.

By default, unless given an explicit starting OID, then the 'snmpwalk' command will display the contents of the 'mib-2' tree, containing most of the IETF-standard management information supported by the agent. When the agent reaches the end of this tree, it will return the first enterprise-specific value, and 'snmpwalk' will recognise that this marks the end of the (implicit) request tree, and stop. No enterprise-specific information will be displayed.

To walk the whole tree, and see all the information that the agent supports, specify a starting point of '.iso' or '.1'.

To walk a specific enterprise subtree, specify the root of this tree as the starting point - e.g:

       snmpwalk -v1 -c public localhost UCD-SNMP-MIB::ucdavis
 

There is more information about particular UCD-specific subtrees in the Agent section.

   FAQ:Applications
   

1. How do I add a MIB?
2. How do I add a MIB to the tools?
3. Why can't I see anything from the agent?
4. Why doesn't the agent respond?
5. I can see the system group, but nothing else. Why?
6. Why can't I see values in the <ENTERPRISE> tree?
7. The agent worked for a while, then stopped responding. Why?
8. Requesting an object fails with "Unknown Object Identifier" Why?
9. Why do I get "noSuchName" when asking for "sysUpTime" (or similar)?
10. Why do I sometimes get "End of MIB" when walking a tree, and sometimes not?
11. How do I use SNMPv3?
12. Why can't I set any variables in the MIB?
13. Variables seem to disappear when I try to set them. Why?
14. Why can't I change sysLocation (or sysContact)?
15. I get an error when trying to set a negative value - why?
16. I get an error when trying to get a string-indexed table value - why?
17. What quotes should I use for string index values?
18. How do I send traps and notifications?
19. How do I handle traps and notifications?
20. My traphandler script doesn't work when run like this - why not?
21. How big can an SNMP request (or reply) be?
22. How can I monitor my systems (disk, memory, etc)?
23. Applications complain about entries in your example 'snmp.conf' file. Why?
24. OK, what should I put in snmp.conf?
25. How do I specify IPv6 addresses in tools command line arguments?