Film-Tech Forum ARCHIVE: How do I find the MAC address of a Barco DP4K-32B?

This is topic How do I find the MAC address of a Barco DP4K-32B? in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=16;t=002810

Posted by Leo Enticknap (Member # 534) on 09-14-2016, 07:55 PM:

Like it says. Its IP address on the network is static, but I want to add a DHCP reservation for that address, so that the router's DHCP server doesn't try to allocate it to a second device that might be connected temporarily (e.g. a visitor's phone or laptop), and thereby break the connection between server and projector.

Problem is that I can't find the MAC address of the wretched thing. It's not on any label on the case of the projector, and it's not in the Installation > Communication tab on Barco Communicator, either.

I tried SSH-ing into the projector to issue an "ifconfig -a" command, but it won't accept the default Service Technician username and password that Communicator will.

Any ideas gratefully appreciated.

Posted by Frank Cox (Member # 6258) on 09-14-2016, 09:49 PM:

Put it on the network, crank it up, and check the log on your dhcp server.

You should find something like this as the last entry:

tail -2 /var/log/messages
Sep 14 20:24:48 world dhcpd: DHCPREQUEST for 192.168.0.8 from 00:13:e8:69:45:51 via eth0
Sep 14 20:24:48 world dhcpd: DHCPACK on 192.168.0.8 to 00:13:e8:69:45:51 via eth0

Notice the mac address is included on both lines in this sample.

Posted by Leo Enticknap (Member # 534) on 09-14-2016, 10:05 PM:

That won't fly, because the "request an address from a DHCP server" function in the Barco is disabled: it has a static address, subnet mask and gateway configured. So the DHCP server in the router has never interacted with the projector at all, and thus there won't be any entry in its log. I don't want to enable that, because if the projector relies on DHCP, then if the router goes out, the connection between the server and projector will be lost, and the show will break down. With DHCP disabled and the addressing entirely static on both the projector and server, they communicate with each other directly through the network switch (to which the router is also connected), without having to go through the router at all.

However, I don't want the router's DHCP server allocating the address that has been configured within the projector as a static one as a dynamic address when someone comes along and connects their laptop, cellphone, or whatever; hence wanting to reserve that IP for that Mac address.

Anyways, I've just cracked it, thanks to a suggestion from a co-worker. Using a command line window on a Windows PC running on the same network, ping the target device, and then enter the command "arp -a": that will list the MAC addresses of all the devices it has communicated with on the local network.

Posted by Steve Guttag (Member # 268) on 09-14-2016, 10:14 PM:

Take you PC and "ping" the IP of the projector (and make sure it pings back).

Then while in the PC's command prompt window, issue the following command:

arp -a

That will return the IPs that your computer has communicated this session with and their respective MAC addresses.

Posted by Frank Cox (Member # 6258) on 09-14-2016, 10:34 PM:

It's a good practice to establish a static range and a dynamic range on a network when you're first setting it up (and assuming that you need both static and dynamic addresses). Then it's easy to tell what's what when you're troubleshooting, i.e. if the address is below 100 then it's static and if it's 101 or above then it's dynamic. Or whatever ranges you decide to use. Then tell your dhcp server to assign dynamic addresses only within your dynamic range and you don't have to worry about a static assignment getting stepped on without having to create a reservation in your dhcp server for each static assignment.

Thirty extra seconds spent editing dhcpd.conf when setting up your network can save you all kinds of time adding static assignments later on.

Posted by Steve Guttag (Member # 268) on 09-14-2016, 10:35 PM:

Take you PC and "ping" the IP of the projector (and make sure it pings back).

Then while in the PC's command prompt window, issue the following command:

arp -a

That will return the IPs that your computer has communicated this session with and their respective MAC addresses.

Posted by David Buckley (Member # 2600) on 09-14-2016, 11:16 PM:

quote: Leo Enticknap
...but I want to add a DHCP reservation for that address, so that the router's DHCP server doesn't try to allocate it to a second device that might be connected temporarily

Your statically allocated addresses and DHCP handed out addresses should be in entirely different address ranges to prevent even a possibility of this occurring.

For example, .1 - .99 static, .100 - .150 DHCP.