You can dump that ping information with the following command in the Terminal: $ arp -a
When your UNIX system pings the other device, it's really using the MAC addresses. It bounces off the target and returns information. As an analogy, think of that as something like a submarine sending out a sonar ping. The way to do this is to open the Terminal app and ping the suspicious IP address. Sounds cool, huh? If you can dump you computer's ARP cache, then you've achieved guru status. Even though there can be 256^3 = 16.7 million devices per manufacturer code, many companies like Apple need more than one of the manufacturer codes. XX or YY ranges from 00 to hexadecimal FF (0 to 255)įor example, the leading XX:XX:XX of 00:22:41 is assigned to Apple. The hexadecimal number is in the form XX:XX:XX:YY:YY:YY where XX:XX:XX identifies the manufacturer and YY:YY:YY identifies the device ID assigned by the manufacturer. My first question was, "What MAC address is this?" The MAC address is the Media Access Control (MAC) address assigned according to the Institute of Electrical and Electronics Engineers (IEEE) standard for identifying Ethernet devices. Little Snitch Doing Its Job - And Creating a Mystery Note: : turns out to be an aggressive Samba search by Path Finder - something that can be suppressed in PF's preferences.) By the way, Little Snitch is a tool I highly recommend. (I'm still working on figuring that part out with the help of Cocoatech Support, maker of Path Finder. Recently, Little Snitch, a security tool, threw up a notice about something odd happening with one of my devices. This HOWTO shows one way to convert that IP address to a MAC address, then a manufacturer. The IP address is known, but little else. Please don’t use “Copy for forum” format.Occasionally, one discovers what may appear to be a rogue or unidentified device on the local home network. It may be that I have found the answer, but not understood what I was seeing, given my, shall we say, not overwhelming experience in C. Sensors.requestTemperaturesByAddress(device) Īpologies for the long post, but this has been frustrating me mightily and I can’t seem to find the answer. I had sucess with the string route.īe that as it may (happy for pointers on that…) my problem is I have the address as a string, but when I get to the “DeviceAddress device =
The simplest and most honest answer to that is my experience in C amounts to not too much more than the code below… I can’t seem to get it to work doing that way. I have the comms part working, although some will probably ask why the received message is going to a string not a char array. The string may be 1 address, or up to 10. Arduino then needs to parse the string is receives, read the temperature from the DS18B20 that corresponds to the address parsed, then build up a string of temps and addresses to return to the database program so it can review and store them. This has probably been asked many times, but I have had no luck finding as answer to my problem in all the discussions I have read (which I’ve been doing most of today…).Įthernet enabled arduino that is sent a message containing a list of addresses (delimited by !) from an initiating database program.