I'm using SNMP (agent) and server but executing snmp agent (snmpwalk or snmpget) on centos,ubuntu system occurs that failure 'Bad operator (DEFINITIONS):'
Confirm if it a problem with your (manager-side) SNMP installation (rather than agent-side) by walking a host on the internet as described at https://stackoverflow.com/a/31615975/449347
If that fails maybe try reinstall your net-snmp.
Related
I'm trying to get my head around SNMP for a project I'm working on. After I failed miserably getting it to work in my company's network, I set up a simple 3-device network to test things on, consisting of two Windows 10 PCs and a manageable switch between them.
I installed the optional feature "SNMP" on both PCs, made sure the service is running correctly and configured both services to accept SNMP queries from each other. I made sure to open up UDP port 161 in both PCs firewalls. Then I got the Net-SNMP binaries in order to use SNMPGET and SNMPWALK. As an alternative, I set up the SNMP extension for PHP through xampp (since I want to use PHP in my project once I get SNMP to work). Finally, I installed wireshark to monitor what exactly is going on and this is what I found:
When I try SNMPGET or SNMPWALK either through cmd or as a PHP command, I always get a timeout message. Wireshark is showing the get-next-request leaving one PC and arriving correctly on the other, so the network connection itself is working fine. But the receiving PC never sends a response. As I said, I'm pretty new to SNMP and I'm at a loss as to why this is happening. As I understand it, the optional feature for Windows 10 comes with its own SNMP agent, correct? If so, what could cause it to simply ignore an incoming request from a valid source IP?
The funny thing is that this even happens when I try to send an SNMP query to 127.0.0.1. I have no idea what I'm doing wrong...
Thanks to the comment of Lex Li, I was able to finally figure out which step I made a mistake with:
When setting up the SNMP service, under the security tab, I had to add 'public' as an accepted community name (with READ-ONLY rights). I figured since 'public' is sort of the standard read-only community, it would be accepted by default, which apparently it is not.
Alternatively, I guess I could have added my own communtiy name, but I didn't try that since I only want to read some values through SNMP anyways and read-only access is all I need for that.
Thank you very much Lex Li, I'm off to continue my project now!
I am receiving traps from the device and want to forward it. Before forwarding I want to set peer address of the source system.
Your SNMP manager could for example add the variable binding snmpTrapAddress.0 to the trap, setting its value to the address of the originating host.
But this is a bit of a hack. If you're writing custom software just to forward traps, I'd suggest that you're reinventing the whell. Consider instead installing net-snmp and letting it forward the traps for you.
I have a small "lab" trying to pentest at home, and I have my main OS and on a VM I'm running Windows XP SP3 (ENG). I use the ms08_067_netapi and the reverse_tcp as a payload. When i use the exploit command this is what I get.
[*] Started reverse TCP handler on 192.168.1.69:4444
[*] Automatically detecting the target...
[*] Fingerprint: Windows XP - Service Pack 3 - lang:English
[*] Selected Target: Windows XP SP3 English (AlwaysOn NX)
[*] Attempting to trigger the vulnerability...
[*] Exploit completed, but no session was created.
What I can understand from that is that the exploit works, but the payload isn't able to function. The first thing I did was to change port from 4444 to 80 just in case, firewall was blocking the payload. I got the same reply, trying with both 80 and 443 as LPORT.
Do you have any suggestions on what else I could do?
https://security.stackexchange.com/questions/112601/ms08-067-netapi-not-performing-as-expected-on-windows-xp-sp1-sp3
The Answer is in that thread
There are many reasons for this exploit to fail, in short:
The target is patched.
'Not supported language' error from the target.
The payload can't execute correctly.
Networking errors 'reverse connection through NAT'.
From experience with the same issue, I recommend to do the following:
Try not to use VMs.
Try another payloads, away from reverse connections.
Try other versions of Windows XP.
Change system languages 'sometime it works!'
Why snmp traps that are generating from the same machines are getting missed in RHEL6.5 ?
What could be the problem ?
Same code is ran on RHEL5.5 traps are not getting missed.
I think that firewall is cause of this behaviour. Try to service iptables stop and service iptables6 stop
I am running Centos 6.3 and attempting to use snmp v3 to query OID's on this server. Running Paessler's snmp tester 5.1.3 I get a no response from host. I have made sure that my iptables do not have any odd firewall settings. I can verify that snmpd is listening on port 161. I have also made sure that SELinux is fully disabled. I am able to install this on Centos 7.1 without any issue. I have done a tail on the messages in var/log/messages and can see incoming traffic for snmpd. I am stumped and have no idea why this will work on one version of this OS but not another. I wonder if anyone has any suggestions.
Thank you