I want to create a program that acts as manager and that queries the router (or sets a trap) to obtain the list of ip connected to it. My router has these functionalities: SNMP v1, v2c, built-in MIB-I, MIB-II agent.
Is it possible to retrieve these informations quering the MIB-II agent of the router in a standard way (not vendor dependent)?
Bye
The Address Translation table (OID .1.3.6.1.2.1.3.1) contains arp table of the device.
This will show you list of all devices from the network, which are (or have been recently) sending some traffic via router.
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I'm developing a system on Xamain in a way that each device can create network service via HttpListner then start listing for incoming calls from other devices on same LAN network. Upon creating the listner we can apply naming convention in the URI so that other devices can filterout non-related services.
The question is there a way to discover all hosts (ip+port) under same LAN having given service's prefix?
I could do it using device specific code for Android via NdsManager class then calling DiscoveringPeers() but I'm thinking why it's not possible to have equivalent functionality in .Net?
I used ZeroConf as source of inspiration to implement Multicasting clients and now all good. The most important is picking up the right Ip address adapted to your Network to multicast. See this table (https://en.wikipedia.org/wiki/Multicast_address).
Broadcasting to 255.255.255.255 was not the required behavior as well as it will not be routed.
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 my network, I want to scan for snmp enabled devices. So is there any single line snmp command, to get list of snmp enabled devices in specific range of IP Address like 172.26.1.1 to 172.26.1.255.
I found a link which says it is possible but it does not mention the command.
https://support.panorama9.com/hc/en-us/articles/203568188-Test-if-SNMP-devices-are-responding-correctly-to-SNMP-queries
Is there any generic OID to achieve this or single snmp command ?
Well, you can try to use the subnet broadcast address but from the SNMP FAQ most devices have this turned off. So this probably won't work very well.
http://www.snmp.com/FAQs/snmp-faq-part2.txt
2.60.12
SUBJECT: How should an agent respond to a broadcast request?
When an SNMP request is sent with a broadcast address, Who is
supposed to respond? Ideally every host in the subnet should respond.
But I notice that it doesn't happen. What is the expected behaviour when
a directed broadcast is done?
Depending on how the agent is written, it may respond, or
just drop the message. Many agents just drop the message.
I believe that is what the SNMP agent in cisco product do.
Another alternative is to try to use nmap to scan for hosts that respond to SNMP as well as attempt to see what community strings they respond to.
https://www.vanstechelman.eu/networking/scanning_for_snmp_services_with_default_community_strings
also
https://nmap.org/nsedoc/scripts/snmp-brute.html
We are trying to create a simulation script where we need to send TCP packet data to the server in way that it appears to be coming from different IP every time.
Basically we need to emulate multiple devices ( with different IP) which are constantly sending data to the server.
The server creates a new connection only for request coming in from a new IP.
What is the best possible way to achieve it ? Is there a way of using proxy servers or some sort of virtualization to accomplish this ?
What you want to use is IP aliasing. This allows you to create virtual network interfaces. Each virtual interface can have one or more IP addresses assigned to it.
This link shows how to do it in Linux.
This link shows how to do it in Windows.
Next your clients need to specify which of your addresses to use. Use getifaddrs() to enumerate the available addresses. Then use the bind() system call on the socket before you do a connect(). This way you can have multiple clients and each one will use a different source IP address. This post has the details.
Is there a way to find out the IP address of a device that is directly connected to a specific ethernet interface? I.e. given one host, one wired ethernet connection and one second host connected to this wired connection, which layer or protocol below IP could be used to find this out.
I would also be comfortable with a Windows-only solution using some Windows-API function or callback.
(I know that the real way to do this would probably via DHCP, but this is about discovering a legacy device.)
Mmh ... there are many ways.
I answer another network discovery question, and I write a little getting started.
Some tcpip stacks reply to icmp broadcasts.
So you can try a PING to your network broadcast address.
For example, you have ip 192.168.1.1 and subnet 255.255.255.0
ping 192.168.1.255
stop the ping after 5 seconds
watch the devices replies : arp -a
Note : on step 3. you get the lists of the MAC-to-IP cached entries, so there are also the hosts in your subnet you exchange data to in the last minutes, even if they don't reply to icmp_get.
Note (2) : now I am on linux. I am not sure, but it can be windows doesn't reply to icm_get via broadcast.
Is it the only one device attached to your pc ?
Is it a router or another simple pc ?
To use DHCP, you'd have to run a DHCP server on the primary and a client on the secondary; the primary could then query the server to find out what address it handed out. Probably overkill.
I can't help you with Windows directly. On Unix, the "arp" command will tell you what IP addresses are known to be attached to the local ethernet segment. Windows will have this same information (since it's a core part of the IP/Ethernet interface) but I don't know how you get at it.
Of course, the networking stack will only know about the other host if it has previously seen traffic from it. You may have to first send a broadcast packet on the interface to elicit some sort of response and thus populate the local ARP table.
Windows 7 has the arp command within it.
arp -a should show you the static and dynamic type interfaces connected to your system.
Your Best Approach is to install Wireshark, reboot the device wait for the TCP/UDP stream , broadcasts will announce the IP address for both Ethernet ports
This is especially useful when the device connected does not have DHCP Client enabled, then you can go from there.
You can also get information from directly connected networking devices, such as network switches with LDWin, a portable and free Windows program published on github:
http://www.sysadmit.com/2016/11/windows-como-saber-la-ip-del-switch-al-que-estoy-conectado.html
LDWin supports the following methods of link discovery: CDP (Cisco Discovery Protocol) and LLDP (Link Layer Discovery Protocol).
You can obtain the model, management IP, VLAN identifier, Port identifier, firmware version, etc.