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TCP Ports scan - SNMP port connection refused

Frequent Advisor

TCP Ports scan - SNMP port connection refused

[ Edited ]

Hi everyone,

I'd like to discover running SNMP agents on some Cisco NW devices. I add the IPs, the DDM finds the devices via ping and it starts a TCP ports discovery. And that's the point when the process fails. It tries to connect to port 161 and gets a rejection of the connection.

Something like that:
Failed to connect to port:161 on host by ip:192.168.255.56 IOException(Connection refused: connect)

What is interesting that the devices do have SNMP enabled, I can access them with SNMP browser (and CW as well), I have a discovery credential for them in uCMDB and I'm able to successfully test it.

Do you have any idea about the root cause? Have ever you faced with this problem? How can I test this 161 udp port from e.g. Windows command line? (without any login, just to see that ther is something behind it) Are there any workarounds?

The uCMDB version is 8.03, the DDM content pack is the 5th.

Many thanks,
Barna

 

 

P.S. This thread has been moevd from Application Perf Mgmt (BAC / BSM) Support and News Forum to CMS and Discovery Support and News Forum. - Hp Forum Moderator

2 REPLIES
Esteemed Contributor

Re: TCP Ports scan - SNMP port connection refused

check snmp cummunity password, is the device snmpwalk-able.. if that 's correct there is known issue that SNMP â v1 or v2â credential, will send only v1 packet please contact HP for a patch.
t#
Little learning is dangerous!
Frequent Advisor

Re: TCP Ports scan - SNMP port connection refused

Thanks, I checked the cred already, it's working fine. The problem is that in the TCP Ports scan discovery module, there is a function in the corresponding script which builds up a connection socket to every known port (taken from that xml in the pattern). And from port 161 (neither tcp - that's fine -, nor udp - that's not :)) it gets an IOException of connection refused.

Nonetheless I got a workaround for this problem, I modified the script that if the port investigated is 161 it should use an external utility called portqry.exe which is able to determine if there is something behind that port.

So finally I made the ports scan and was able to discover the snmp ports as well. I have another problem now, but I think I'll try to solve it first on my own and then post the solution/ask again here.

Thanks again,
Barna
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