find IP address of device

[J V]

Hello,

What is the easiest way to find the IP address of a device that is configured with a static IP, but you do not know which one...

It is a question at my work, where we got a couple of second-hand EV chargers (specific chademo V2G for research purpose) but we cannot access the webpage for the configuration as the devices do not respond to their default IP address and are not configured for DHCP; probably their IP was changed to a different static IP. Currently, we are running an IP scanner over a local network (192.168.x.x already done, next will be 172.16.x.x, but that will take a lot longer, and hopefully we don't have to scan 10.x.x.x - and this is still assuming it was configured with a private IP). We do not have the procedure to revert to factory settings (the question was sent to the manufacturer).
WireShark did not seem to reveal anything of interest....

Any thoughts?

Thanks,

Jörg

[Jan W.]

Hi Jörg,

an IP scanner might not work as expected and does not show any useful information. You should connect a PC with Wireshark to the device directly or via layer 2 switch (both devices need to be in the same broadcast domain).

At first you should start wireshark and capture packets in promiscous mode, then turn on the device. Most devices try do do a few task when they are turned on. Watch for ARP packets (set display filter to arp). It might be easier if you combine that filter with an exclude of the local PC, e.g.

arp && !(eth.src == 2c:23:3a:11:22:33)

Replace the MAC address 2c:23:3a:11:22:33 with the MAC address of your PC. Then you should see a few ARP requests from the device and within a few seconds you get the IP address.

If you have some skills on port mirroring and a switch that is capable, this might also be an option. With a google translator this artice in Loxwiki might also be helpful: https://loxwiki.atlassian.net/wiki/s...er+im+Netzwerk

Cheers,
Jan

[J V]

Thank you for your reply!

I did your approach before seeing your answer and I managed to find the IPV6 address.

I connected the device and my pc directly, then ran Wireshark and started the device. In Wireshark I saw a record with a mac address that was not mine, but it also contained an IPv6 address. I could use that one to go to the web-interface of the device (yes, you can enter an IPv6 address in a browser but you have to put it between square brackets!), and from there I could enter the network configuration of the device.
Weirdly enough it was configured to receive an IPv4 via DHCP, but it did not take one when being put in a network with a DHCP server. But after just saving the configuration again, it correctly gets an IPv4 address from my DHCP server.

[Jan W.]

It sounds weird that the device was configured with an IPv6 address, but at the end it doesn‘t matter - you were able to get on the device and solve your Problem! 👍

[J V]

One additional problem was that I did not know the broadcast domain that was set on it... I was also did not expect it to be configured in IPv6, but when I saw it I immediately googled how to enter an IPv6 address in a browser. With the laptop in the 10.x.x.x network and - as it turned out later - the device in DHCP, the IPv6 was the only thing that popped up. Surprisingly, the configuration interface for the network does not offer any settings regarding IPv6... Well, at least I found it. Thanks again for the help!