I want to configure SNMP traps on PFsense, to do it I have done below things.
Enable SNMP Demon (Without doing it it is not allowing to enable traps)
A. Given poling port number (161)
B. Given Read community string. (mypfsense)
Enable SNMP Traps
A. Given Trap Server IP. (192.168.0.100)
B. Given poling port number (162)
C. Given Read community string. (mypfsense)
On windows 2008 server I have install Ireasoning MIB Browser.
Turn on Trap receiver on port number 162.
But at here I was not getting any update on trap receiver so I have check through....
send test trap using ireasoning trap sender, and i got trap in trap receiver.
I was not getting PFSense traps, so then after I have
Add feature in server 2008 snmp service, and configure it as below.
A. services.msn > snmp service property > Security tab > accept community name -> added the community "mypfsense" as Read Only.
Then after I repeat the steps 4 and 5, both are behaving as it is.
So after all I am not getting traps of PFSense.
I am requesting you to please help me to configure it.
Note: I have check through MIB Browser that poling is working from the 2008 server it gives output of get next, walk, get bulk etc. etc...
Thanks and Regards,
Harshit Choksi.
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 setting up port scanner for remote server in my application using Go. I am using DialTimeout function in Go net package to check whether a remote host port is opened or not. The result is fine with success case. But, if i/o timeout happens, I need to identify whether
The port is closed (No service is running) or
Port is blocked (Firewall filtered) or
Due to internet connectivity down in local system where the application is running.
Have tried nmap cli command, I can able to differentiate those failure 3 cases exactly.
nmap command tried: nmap -sA -p port_number host_ip
I found a Go 3rd party libray to use nmap.
But, I don't want to use nmap in my application. Are there any other alternatives in Go to exactly differentiate those 3 cases?
In the simple world
Lets assume you want to scan a Linux system.
If you get an ICMP message type 3 code 3, the firewall explicitly told you:
Hi, I am the firewall of your target host. The host is running. I hereby inform you that you (potentially amongst others) can not access this port. So now that you know you should quit your connection attempts. However, I won't tell you wether it is because there is no service running behind it (in which case my response is simply a courtesy) or because I was told to deny you access. Goodbye!
The port is closed if you do not get above answer and can not make a connection. I hence strongly advice to use context.WithTimeout to make a connection.
In the real world
However, this only applies if the admin of the target host did not change the ICMP message type to respond with - or chose just to drop any packets coming from sources which are not allowed to access the respective service. In the latter case, there is no way for you to know wether the port is closed or filtered.
All of the above only applies if we are talking of an iptables based firewall on the target system with default settings.
Now assume something which is by far more likely: A border firewall plus a local firewall. The border firewall might send other ICMP messages (or, again, simply drop your packages). Those rules apply additionally to the rules of the local firewall. So it is a misconception that you are actually scanning a host. It is more accurate to say that you scan the services reachable via a specific IP.
EDIT
Why would one send an ICMP message explicitly rejecting connection attempts?
There are various reasons to come to that decision. There is a good answer on serverfault.com
About 5 days ago, OpenNMS Horizon 22.02 on Ubuntu 18.04.1 LTS stopped accepting traps from network elements. No changes were made to configuration or underlying operating system to my knowledge.
There are about 125 network elements, all Cisco, sending traps.
So far I have checked the following:
tcpdump shows the traps coming into the interface on port 162
Turned on Debug for trapd.log and incoming traps from network elements do not create any log entries
Traps sent with send-trap.pl from the localhost create traps that flow all the way to events
Traps sent with snmptrap either on localhost or another host create log entries that flow all the way to events. The other host is using the same interface that the network elements are using.
ss -lnpu sport = :162 shows an open UPD "UNCONN"
sudo lsof -i :162 shows a single listener java process
Startup of trapd does not seem to show any warnings in the log
I have verified that the ufw and iptables are off
I have updated OpenNMS to 22.04 and updated Ubunutu with no relief
Restarted OpenNMS many many times...
I moved Trapd startup after Asterisk in service-configuration.xml based on this
All of this seems similar to this. I think the last commenter on that thread asked about comparing the successful and unsuccessful traps in Wireshark which I have not done but all of the traps that are being sent have worked hundreds if not thousands of times until November 6th.
Is there anywhere else to look for errors as to why Trapd is not accepting traps? I think I have ruled out network issues.
I created a new Ubuntu 18.04 VM, updated it and then installed Horizon 23.01 fresh. I pointed my stream of traps at it and it behaves the exactly the same way, none of the traps create any log entries on the trapd.log with the level set to debug. Tcpdump shows the traps coming to the interface.
Issue Resolved.
The underlying operating system lost its static route for the subnet that the traps were coming from. OpenNMS had a route back to the subnet but not via the path that the traps were coming in from. Once the static route was restored, traps started working again and were flowing all the way to events.
My OpenNMS system is running on Windows Server 2012 and I am doing most of my configurations through the web interface.
I have configured an SNMP community associated with a range of ip addresses for the node I want to monitor. I have specified a string for this community. I have added the node (which contains multiple ip addresses) for provisioning. I have added the node to the default data collection group. However, when I try to navigate to the node, rescan it, and manage data collection per interface, I cannot view the node as an option from which to collect data. I also do not see SNMP data on the node availability graphs, only ICMP data. How should I approach this problem. Are there any additional files I need to edit?
If any of you have some knowledge of OpenNMS, I would appreciate the help. I have only been using OpenNMS for 2 weeks now, and I have very little knowledge of SNMP or networking, though I am learning more every day.
First of all, it is important to ensure your OpenNMS as SNMP access to your Device you want to monitor. You can verify this by running the following command from the CLI off your OpenNMS server:
snmpwalk -v 2c -c <your-community-string> <your-ip-interface>
If you don't see any output or a timeout, you have connectivity issues which can be firewalls between your OpenNMS and the device you want to monitor. It can also be the SNMP Agent on your Device does not allow access from your OpenNMS servers IP address.
As I'm reading your Node has multiple IP interfaces you have provisioned. You can define an attribute "SNMP Primary" which means:
P: It is the primary interface and when it is reachable, OpenNMS will try to fetch all SNMP performance data from this interface
S: It is set as secondary, it means SNMP is available but will only be used to fetch SNMP performance data if the primary interface is down
N: Not used for SNMP performance data collection
By default OpenNMS detects also services like SNMP. The SNMP service is assigned to the interface when it is possible to fetch the System Object ID (sysoid) .1.3.6.1.2.1.1.2.0 from the given IP interface using the SNMP community you have configured by the IP address in the WebUI. You can troubleshoot this on the CLI using the snmpget command from your OpenNMS server like this:
snmpget -v 2c -c <your-community-string> <your-ip-interface> .1.3.6.1.2.1.1.2.0
If you don't get a result, OpenNMS will not detect the SNMP service. OpenNMS will only try to collect SNMP performance data from an IP interface when the SNMP service is associated.
Hope this helps for further troubleshooting.
In Zabbix Server 3, I have a linux host monitored through SNMP.
The SNMP OID of the monitored MIB is as below:
SNMPv2-SMI::enterprises.94.7.1.4.2.1.5.1 = STRING: "CLUSTER STARTED (RESTARTED)"
I have configured this SNMP OID to be monitored for every 10 minutes. The Zabbix server is sending a SNMP get-request and the linux host replies back. The timestamp is updated in this case in Zabix>Monitoring>Latest Data section of Zabbix dashboard
I also have an SNMP trap defined for this event.
I restarted the cluster in the linux host, which triggered an SNMP trap message to zabbix and the event is captured in /var/log/zabbix/snmptrapfmt.log of zabbix server. But the Zabix>Monitoring>Latest Data section of Zabbix dashboard still has old timestamp for latest data. The new value is not updated from SNMP trap.
Is there any separate configuration needed for this?
I am using zabbix appliance 3 as zabbix server
The first item you showed, the one that polls SNMP, should not be relevant for trap processing.
Regarding the second item (snmptrap), make sure you have started SNMP trapper (StartSNMPTrapper parameter in the server configuration file).
Also check that Zabbix server points at the location where you traps are written with the parameter SNMPTrapperFile.
If all that is configured, check the server log - if a trap is written there, it was not matched to your item - in that case, check your regexp against the trap data and make sure the IP address Zabbix sees the trap from matches the SNMP interface address for that item.