Currently I am designing layer 2 topology discovery application. LLDP protocol helps me to discover layer 2 neighbor devices. So far I have observed that LLDP is only available in Layer 2 Device Lan Ports but Wirless port does not provides LLDP information.
As per LLDP, if more neighbor device are connected to the same port (i.e By the help of HUB ) on the local device, then it may not give all neighbor information. This may not be suitable for Wireless device, because WLAN AP device connects many more client on the same port.
Also, WLAN AP itself provides all connected client information on their private MIBS and WLAN client device says who is my current WLAN AP. This would be sufficient to know the neighbor device and thus no need of LLDP in WLAN port.
Please help to me know, is my assumption correct? and Is there any wireless port provides LLDP information?
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We have laptop installed with two NIC (WLAN and LAN) which connects to different networks. so it has two different IPs.
In this condition, If we perform SNMP broadcast discovery(using 255.255.255.255) to identify the SNMP compliant devices. We get only the device listed in WLAN and LAN interface IP ranges are not detected.
How can I get all the SNMP-compliant devices connected in the WLAN and also LAN network through SNMP broadcast discovery(using 255.255.255.255) ?
Thank you
I can have a USB wireless connection to visit internet and an Ethernet wired connection to
the intranet(dynamic IP). However, they can NOT co-exist.
Every time I want to use one of them, I have to unplug the other one.
This is so annoying! Does anyone has a solution to let them compatible that computer uses
the wifi to visit internet and wired to ssh to the other local servers?
thanks in advance!
Might want to check the IP addresses of these two interfaces: they should fall into different subnets. For example, 192.168.x.y for wireless and 10.10.m.n for wired. Otherwise your outgoing packets may go to the wrong interface.
i am working on a network discovery program which employs snmp to discover devices in the network. My program takes the router-ip as input, scans the iprotetable(iprouttenext hop),to determine if any other routers are connected to it. for non router devices (like switch) the algorithm scans the arptable (ipnettomediatable) of the router, but cant find the connected switch unless i ping from the switch to the router. is there any way where i can determine the device connected directly to the router ..?
Getting the devices connected to a router or switch is not that easy. Switches usually maintain a MAC forwarding database where it stores which MAC address has been seen on which switch port. This table can be easily read by using the bridge MIB. Unfortunately, there are several issues to take care of:
Those entries disappear again, when a device to the switch has been switched off or is simply not communicating. Usually, the entries in the MAC forwarding tables age out after 5 minutes or so.
The fact that a MAC address has been seen on a switch port doesn't mean that the device having the mac address is directly connected to the port. There might be any number of other switches, routers or hubs inbetween.
Some manufacturers like Cisco or HP use their own protocols to determine the network topology. There are several protocols (that area usually also available through a SNMP MIB):
CDP (Cisco Discovery Protocol): This is a proprietary protocol developed by Cisco to expose network topology information. Some vendors licensed this technology and implement that protocol in their products.
LLDP (Link Layer Discovery Protocol): A standard similar to CDP, but without paying Cisco license fees :-)
And many more. I know kthat Extreme Networks has their own protocols and I am pretty sure that other vendors have them as well.
The problem with those protocols is when you have a mixed environment. Cisco switches talking CDP do not understand Extremen Network's protocol and vica versa.
If your goal is to find IP addresses to discover, then you might use the ARP caches for routers. Scanning the ARP caches for switches makes no real sense, because they're operating on layer 2.
I was using broadcast message for my java snmp agent
I need to monitor how many smart phones are connected to a wireless network in a certain area. I found out that Zigbee can be used to accomplish this task. I need to at least differentiate each phone connected. What do I need to do?
Without knowing anything in regards to Zigbee, you could use the BSSID of the device as your unique identifier. Every WiFi radio has a unique BSSID. Just a thought.
ZigBee (802.15.4) and Wi-Fi (802.11) are different networking standards. They both use 2.4GHz, but a ZigBee radio won't be able to identify nodes on a Wi-Fi network.
Zigbee (IEEE 802.15.4) and WiFi (IEEE 802.11) are two different PHY/MAC specifications. The first thing you have to do is:
Build a gateway between the Zigbee and WiFi networks.
Each smartphone should be capable of connecting to the Zigbee network.
Each smartphone should act as end device and Zigbee controller
should track the position of each smartphone. This controller should
be connected to Wifi via gateway [1]. Then you can easily track
number of smartphones connected to a network.
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.