How To Find Unknown Ip Address

Hey all, I have some manufacturing equipment that needs to get on our network. These basically all came preconfigured with static IP and subnets unknown to me; some may exist able to accept DHCP, simply I don't know if that'due south the instance for all of them. The PLCs contain a broad array of industrial ethernet switches with which I have zero experience. I need to go into the GUI of these machines and reset the static IP so it can communicate on the VLAN I've created.

My question is: How do I discover out what these IP and subnets are that take been statically set on these devices? For all I know, they could be form A, B, or C individual addresses. I was thinking connecting the devices directly to my laptop with an ethernet cablevision and running a wireshark capture, looking for ARP broadcasts. Simply wouldn't my laptops NIC demand to be set up on the same network as the device it's connecting to, i.e. if the device is on 192.168.0.0/sixteen network, my laptop would need to be on that subnet every bit well, in order to even run into the broadcast traffic?

Any advice is profoundly appreciated.

9 Replies

Troy Jollimore Jan 23, 2020 at 14:31 UTC

Full general Networking expert

Since y'all're looking directly at traffic coming from that NIC, Wireshark tin can capture it in promiscuous style.

Otherwise, best thing to practice is to inquire the manufacturer. No manner they shouldn't be able to aid you. Secondly, the ethernet setup inside of the device shouldn't actually exist toyed with. The only interface yous should be interested in connecting to is their WAN/LAN interface. Industry standard is to utilise DHCP, or have it ready as 192.168.1.10 or something. Yous could set up your laptop upwardly to a couple of commonly used subnets and so practise a subnet ping scan.

celtek January 23, 2020 at fourteen:42 UTC

The thing with the manufacturer's is that the PLCs are mish mash custom pieces that were put together from dissimilar vendors. Allen Bradley, Siemens, and other international fabricators and vendors. And across the half-dozen or seven machines I'm dealing with, none of them are the aforementioned or have the same equipment inside. I remember the easiest bet would be to endeavor and get a packet capture of ARP traffic.

edit: I concur, I won't be messing with any of the internal ethernet traffic. At that place's a lot of ethernet communication going on internally in these cabinets, then that would not be ideal. The just thing I'd like to deal with is the LAN/WAN interfaces of the switches.

spicehead-Greg Jan 23, 2020 at fourteen:52 UTC

I would to the the documentation of the printers and find the key combination to default all the settings, thus restoring its ability to accept a DHCP address.

celtek wrote:

Hey all, I accept some manufacturing equipment that needs to get on our network. These basically all came preconfigured with static IP and subnets unknown to me; some may exist able to accept DHCP, but I don't know if that's the example for all of them. The PLCs comprise a broad array of industrial ethernet switches with which I have null experience. I need to get into the GUI of these machines and reset the static IP and so it can communicate on the VLAN I've created.

My question is: How do I observe out what these IP and subnets are that accept been statically set on these devices?

Incorrect question. Side by side one?

Where did yous create this VLAN, on your current switches or on such new preconfigured industrial ethernet switch?

What do you mean that those machines came all preconfigured with static IP and subnets?

Who ordered those machines? Which preconfiguration did they inquire for?

Get to that information of those ordering that preconfiguration and inquire for their network design they ordered and for contact info.

It's very probable that network design of your industrial ethernet is completely dissimilar of what you know. Usually, these are designed in a manner you would e'er want to prevent in a traditional non-industrial ethernet network. Those machines should have come up with (electronic) documentation which teaches you your options of technology an appropriate and supported industrial ethernet network. I further expect that the purchases had some project engineer coordination involved in that buy process which might be from your company or some external engineering function. Then such different network designs take their purpose and are meaningful. And it doesn't seem to me a adept thought to have such networks fully integrated with traditional ethernet networks. There should be industrial network gateways for such connections instead.

I'm used to that manufacturing surroundings is regulated as information technology may involve risks to human life of workers. Merely people authorized are then immune to exercise the setup of those machines resp. networks. Are you already authorized or only designated and need to pass training to get qualified and authorized? Preparation should have told yous which constraints and regulations to respect for applied science such an industrial network resp. the subset of applying all those technology decisions some other qualified political party has already fabricated. Usually, the buy club of manufacturing machines includes not only commitment but besides setup and integration of that equipment, usually integrating somebody from your company too as somebody from the vendors companies. The purchase order may have included to teach such people of your company so that they may do either the setup or also the applied science instead of take the vendors (or some ordered external engineering science office) do that role. So if those vendors were not ordered with engineering nor setup, ask in your company those issuing those purchase orders when you'll get which training in guild to get authorized to do what you lot've been designated to practice in the machines setup, technology and integration. If your task is solely that integration, your preparation should provide you some basics of the industrial network technologies involved (probably not just industrial ethernet), and in depth of those industrial gateways and switches.

I oasis't worked in such an productive environment, only in advisable examination labs of suppliers. I didn't get formal preparation and only read a subset of the manuals. I had no difficulty in understanding them but I'1000 used to embedded systems and networks since transitioning from school to university. And I expect that my knowledge gets outdated as new options for industrial networks should become bachelor starting in the yr 2020. I expect to go invitations to a corresponding off-white for end of next month which is 1 relevant for such components and is one of the largest of its kind for my continent.

If they came with a network preconfigured on them including switches, your best bet would exist to join their network to yours, not modify information technology in whatever way.

Y'all will need the documentation and a design professional to integrate the network into yours. The design side of things should only take a few hours, but you need complete documentation showtime or that will drag out and price you coin.

celtek wrote:

My question is: How do I find out what these IP and subnets are that accept been statically set up on these devices? For all I know, they could be class A, B, or C private addresses. I was thinking connecting the devices directly to my laptop with an ethernet cable and running a wireshark capture, looking for ARP broadcasts. Merely wouldn't my laptops NIC demand to be set on the same network equally the device it's connecting to, i.east. if the device is on 192.168.0.0/16 network, my laptop would need to be on that subnet too, in club to even see the broadcast traffic?

I'm assuming that this is some kind of equipment that yous purchased used and that's why it is pre-configured. My starting time stride would be to accept the vendor help me become into the panel of the device and set the TCP/IP settings to something that matches my network.

If that's not an option, then you lot have it exactly correct. Plugging directly into the device with a laptop and doing a parcel capture will give y'all everything yous need to constitute connectivity. Y'all don't need to be on the same subnet--just wait for the ARP broadcasts. You will run into the machine sending ARPs of the format: "Who has <IP1>, tell <IP2>". IP1 is the IP that the device thinks is its default gateway and IP2 is the device's IP. Then just option a mask that puts both of those IPs in the same subnet (most likely it'll exist a /24), and yous're good to go.

celtek Jan 24, 2020 at 18:31 UTC

All I want to do is configure the uplink port on these mini switches to communicate with the segmented network I created. With all due respectscheff1, you're going way beyond the scope of what I'm asking.

I was able to connect to a machine with my laptop with an ethernet cable and get the IP address of it's spider web interface past sniffing the circulate ARP traffic with Wireshark. With this, I should have the information I need to move frontward. Thanks.

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My experience with industrial robots and computer network continued industrial machines is that there is always very good documentation available and manufacturer's support is by and large excellent.

I meet no problem to detect instructions on how to bank check current network configuration on the device and change it.

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