Ok here's the Apple pcap for a working implementation.
tcpdump -r airport.dhcp.pcap
tcpdump: WARNING: snaplen raised from 116 to 1500
12:26:04.010316 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0x5fc12750
secs:28 vend-rfc1048 DHCP:DISCOVER LT:86400 HN:"x" PR:SM+TZ+DG+DN+NS+HN+WNS
MSZ:1500 CID:1.32.201.208.21.60.163 [tos 0x10]
12:26:27.806275 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0xb4e0b61a
vend-rfc1048 DHCP:DISCOVER LT:86400 HN:"x" PR:SM+TZ+DG+DN+NS+HN+WNS MSZ:1500
CID:1.32.201.208.21.60.163 [tos 0x10]
12:26:33.010312 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0xb4e0b61a secs:6
vend-rfc1048 DHCP:DISCOVER LT:86400 HN:"x" PR:SM+TZ+DG+DN+NS+HN+WNS MSZ:1500
CID:1.32.201.208.21.60.163 [tos 0x10]
12:26:44.010312 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0xb4e0b61a
secs:17 vend-rfc1048 DHCP:DISCOVER LT:86400 HN:"x" PR:SM+TZ+DG+DN+NS+HN+WNS
MSZ:1500 CID:1.32.201.208.21.60.163 [tos 0x10]
12:26:49.707196 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0x5886fe16
vend-rfc1048 DHCP:DISCOVER LT:86400 HN:"x" PR:SM+TZ+DG+DN+NS+HN+WNS MSZ:1500
CID:1.32.201.208.21.60.163 [tos 0x10]
12:26:55.010311 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0x5886fe16 secs:6
vend-rfc1048 DHCP:DISCOVER LT:86400 HN:"x" PR:SM+TZ+DG+DN+NS+HN+WNS MSZ:1500
CID:1.32.201.208.21.60.163 [tos 0x10]
12:27:03.010312 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0x5886fe16
secs:14 vend-rfc1048 DHCP:DISCOVER LT:86400 HN:"x" PR:SM+TZ+DG+DN+NS+HN+WNS
MSZ:1500 CID:1.32.201.208.21.60.163 [tos 0x10]
12:27:12.010312 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0x5886fe16
secs:23 vend-rfc1048 DHCP:DISCOVER LT:86400 HN:"x" PR:SM+TZ+DG+DN+NS+HN+WNS
MSZ:1500 CID:1.32.201.208.21.60.163 [tos 0x10]
12:27:57.010496 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0x34861165
vend-rfc1048 DHCP:DISCOVER LT:86400 HN:"x" PR:SM+TZ+DG+DN+NS+HN+WNS MSZ:1500
CID:1.32.201.208.21.60.163 [tos 0x10]
12:27:57.227277 202.63.66.1.bootps > 255.255.255.255.bootpc: xid:0x34861165
flags:0x8000 Y:202.63.67.36 S:172.21.116.42 ether 20:c9:d0:15:3c:a3
vend-rfc1048 DHCP:OFFER SM:255.255.254.0 DG:202.63.66.1
NS:119.40.106.35,119.40.106.36 NTP:125.253.59.254 LT:600 SID:202.63.66.1
MSZ:1500 CID:1.32.201.208.21.60.163 [tos 0xc0]
12:27:57.228177 0.0.0.0.bootpc > 255.255.255.255.bootps: xid:0x34861165
vend-rfc1048 DHCP:REQUEST SID:202.63.66.1 LT:86400 RQ:202.63.67.36 HN:"x"
PR:SM+TZ+DG+DN+NS+HN+WNS MSZ:1500 CID:1.32.201.208.21.60.163 [tos 0x10]
12:27:58.075046 202.63.66.1.bootps > 255.255.255.255.bootpc: xid:0x34861165
flags:0x8000 Y:202.63.67.36 S:172.21.116.42 ether 20:c9:d0:15:3c:a3
vend-rfc1048 DHCP:ACK SM:255.255.254.0 DG:202.63.66.1
NS:119.40.106.35,119.40.106.36 NTP:125.253.59.254 LT:600 SID:202.63.66.1
MSZ:1500 CID:1.32.201.208.21.60.163 [tos 0xc0]
On Thu, May 11, 2023 at 12:20:48AM +0200, Sebastian Benoit wrote:
> i think that putput does not help mmuch because it does not show the DHCP
> packet contents.
>
> You could write the capture to a file with "-w filename" and then copy the
> file to the OpenBSD box for printing with "-r filename". Or send the raw
> pcap file.
>
> /B.
