FAQ:Agent 12

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How can I run AgentX with a different socket address?

There are two sides to an AgentX connection, and they need to agree about which socket address to use. So if you want to use a different socket, you need to configure both parties accordingly.

The socket that the Net-SNMP master agent uses to listen for AgentX registrations (and send appropriate requests) can be specified using the option '-x'.
The command

               "snmpd -x tcp:localhost:705 ...."

would start the agent listening on the TCP port 705 for connections from the local system.
The same effect can also be obtained by adding the line

               agentxsocket tcp:localhost:705

to the file snmpd.conf.

This also holds when the Net-SNMP agent is running in "subagent" mode, to specify the socket to register with (and receive requests from).
So a subagent might connect to the master agent above (both running on the same host), using:

               "snmpd -X -x tcp:localhost:705 ...."

A subagent running embedded within some other application will typically not understand the same command-line options, so would need to set the same configuration programmatically:

      netsnmp_ds_set_string(NETSNMP_DS_APPLICATION_ID,
                            NETSNMP_DS_AGENT_X_SOCKET, "tcp:localhost:705");

With the example subagent code from the Net-SNMP tutorial, this line would be added immediately before the 'init_agent' call.

The same approach can also be used to listen on a different named socket, using:

               agentxsocket /tmp/agentx
               agentxperms 770 770 myuser mygroup

or

               snmpd -x /tmp/agentx ....

or

      netsnmp_ds_set_string(NETSNMP_DS_APPLICATION_ID,
                            NETSNMP_DS_AGENT_X_SOCKET, "/tmp/agentx");

as appropriate.

   FAQ:Agent
   
  1. What MIBs are supported?
  2. What protocols are supported?
  3. How do I configure the agent?
  4. How do I remove a MIB from the agent?
  5. I've installed a new MIB file. Why can't I query it?
  6. How do I add a MIB to the agent?
  7. What's the difference between 'exec', 'sh', 'extend' and 'pass'?
  8. What's the difference between AgentX, SMUX and proxied SNMP?
  9. What is the purpose of 'dlmod'?
  10. Which extension mechanism should I use?
  11. Can I use AgentX when running under Windows?
  12. How can I run AgentX with a different socket address?
  13. How can I turn off SMUX support?
  14. How can I combine two copies of the 'mib2' tree from separate subagents?
  15. What traps are sent by the agent?
  16. Where are these traps sent to?
  17. How can I send a particular trap to selected destinations?
  18. When I run the agent it runs and then quits without staying around. Why?
  19. After a while the agent stops responding, and starts eating CPU time. Why?
  20. How can I stop other people getting at my agent?
  21. How can I listen on just one particular interface?
  22. The agent is complaining about 'snmpd.conf'. Where is this?
  23. Why does the agent complain about 'no access control information'?
  24. How do I configure access control?
  25. How do I configure SNMPv3 users?
  26. The 'createUser' line disappears when I start the agent. Why?
  27. What's the difference between /var/net-snmp and /usr/local/share/snmp?
  28. My new agent is ignoring the old snmpd.conf file. Why?
  29. Where should the snmpd.conf file go?
  30. Why am I getting "Connection refused"?
  31. Why can't I see values in the UCDavis 'extensible' or 'disk' trees?
  32. Why can't I see values in the UCDavis 'memory' or 'vmstat' tree?
  33. What do the CPU statistics mean - is this the load average?
  34. How do I get percentage CPU utilization using ssCpuRawIdle?
  35. What about multi-processor systems?
  36. The speed/type of my network interfaces is wrong - how can I fix it?
  37. The interface statistics for my subinterfaces are all zero - why?
  38. Does the agent support the RMON-MIB?
  39. What does "klread: bad address" mean?
  40. What does "nlist err: wombat not found" (or similar) mean?
  41. What does "Can't open /dev/kmem" mean?
  42. The system uptime (sysUpTime) returned is wrong!
  43. Can the agent run multi-threaded?
  44. Can I use AgentX (or an embedded SNMP agent) in a threaded application?