Op 12/5/2012 7:50 PM, Martin Pelikan schreef:
Did you make sure you don't have any bridge accidentally between those
two subnets (two cards going into the same switch or VLAN). Especially
in buildings with complex wiring this mistake can easily happen. Local
broadcast (255.255.255.255) packets are never forwarded to different
interfaces (if not in a bridge).
Hi Martin,
Facepalm... Thank you for your reply. Turns out interfaces dc0, xl0 and
both subnets all came together on the same switch. The memories are
starting to come back now. It was a long time ago in a galaxy far, far
away. I was tired of mixing up the interfaces. Shoved everything in the
switch. Made a mental note I should setup a VLAN for this. Forgot this
within the hour.
Anyway, the tcpdump on xl0 is now quit. This is a tcpdump on the dc0
interface with the -n and -e options you suggested:
$>sudo tcpdump -n -e -i dc0 -vvv -s 1500 '((port 67 or port 68) and
(udp[38:4] = 0x19667568bf))'
tcpdump: listening on dc0, link-type EN10MB
22:38:08.282731 00:19:66:75:68:bf ff:ff:ff:ff:ff:ff 0800 343:
192.168.2.6.68 > 255.255.255.255.67: [udp sum ok] xid:0x2b6e0b3f
C:192.168.2.6 vend-rfc1048 DHCP:REQUEST CID:1.0.25.102.117.104.191
HN:"xccube" T81:0,120,25443,30050,25902 VC:77.83.70.84.32.53.46.48
PR:SM+DN+DG+NS+WNS+WNT+WSC+RD+SR+249+VO VO:220.1.0 (ttl 64, id 41874,
len 329)
22:38:08.283711 7c:4f:b5:93:47:b8 ff:ff:ff:ff:ff:ff 0800 342:
192.168.2.254.67 > 255.255.255.255.68: [udp sum ok] xid:0x2b6e0b3f
C:192.168.2.6 Y:192.168.2.6 S:192.168.2.254 ether 00:19:66:75:68:bf
vend-rfc1048 DHCP:ACK SID:192.168.2.254 LT:4294967295 SM:255.255.255.0
DG:192.168.2.254 NS:192.168.2.254 (ttl 64, id 6765, len 328)
22:38:10.822393 7c:4f:b5:93:47:b8 ff:ff:ff:ff:ff:ff 0800 342:
192.168.2.254.67 > 255.255.255.255.68: [udp sum ok] xid:0xca7dd1a6
C:192.168.2.6 Y:192.168.2.6 S:192.168.2.254 ether 00:19:66:75:68:bf
vend-rfc1048 DHCP:ACK SID:192.168.2.254 LT:4294967295 SM:255.255.255.0
DG:192.168.2.254 NS:192.168.2.254 (ttl 64, id 6766, len 328)
Thanks again!
Cheers,
Jasper
