<i>
</i>:~ $ tcpdump -veni eth0 udp portrange 67-68 | grep -E ''[0-9]\{1,2\}\:[0-9]\{1,2\}\:[0-9]\{1,2\}\.[0-9]\{1,6\}'|Client-Ethernet-Address'
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
11:28:52.427217 ##:##:##:79:##:46 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 391: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 377) Client-Ethernet-Address c8:0e:14:8a:34:xx
11:28:53.275242 ##:##:##:79:##:46 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 391: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 377) Client-Ethernet-Address 34:81:c4:c8:b1:xx
11:29:03.231591 ##:##:##:79:##:46 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 391: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 377) Client-Ethernet-Address 24:65:11:56:0c:xx
11:29:21.482981 ##:##:##:79:##:46 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 328) Client-Ethernet-Address f4:f2:6d:94:b3:xx
11:29:27.188854 ##:##:##:79:##:46 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 391: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 377) Client-Ethernet-Address 24:65:11:19:d9:xx
11:29:32.177726 ##:##:##:79:##:46 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 391: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 377) Client-Ethernet-Address bc:05:43:bb:2f:xx
11:29:34.218642 ##:##:##:79:##:46 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 391: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 377) Client-Ethernet-Address c0:25:06:1c:15:xx
11:30:13.962983 ##:##:##:79:##:46 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 391: (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 377) Client-Ethernet-Address 34:81:c4:d6:6e:xx