Earlier I was setting up a PXE boot server that was connected to two networks and wanted to hand out DHCP addresses only on the second interface which in this case was eth1. The primary interface on the server is eth0 however that Ethernet port is attached to a switch that already has a DHCP server connected to it so I needed to make sure that the DHCP server only replies to requests on eth1. Use the dhcpd.conf configuration option below to specify the Ethernet interface that dhcpd will listen for and reply to DHCP and/or BOOTP requests.
Earlier while troubleshooting a possible issue with VMWare Player on Ubuntu Linux I needed to sniff broadcast traffic. The goal was to see if there were multiple MAC addresses sending out broadcast traffic after VMWare Player was installed on Ubuntu even without a VM actually running. Below is a quick example of how to sniff Ethernet broadcast and multicast traffic using tcpdump.