dhcp パケットをキャプチャするメモ

tcpdumpの場合

$ sudo tcpdump -i wlp3s0 port 67 or port 68 -e -n
[sudo] password for matoken:
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on wlp3s0, link-type EN10MB (Ethernet), capture size 262144 bytes
21:07:44.898511 00:23:15:5b:a6:60 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 00:23:15:5b:a6:60, length 300

dhcpdump も読みやすくて便利

$ sudo dhcpdump -i wlp3s0
TIME: 2019-04-10 21:17:17.398
IP: 0.0.0.0 (0:23:15:5b:a6:60) > 255.255.255.255 (ff:ff:ff:ff:ff:ff)
OP: 1 (BOOTPREQUEST)
HTYPE: 1 (Ethernet)
HLEN: 6
HOPS: 0
XID: 011d073a
SECS: 0
FLAGS: 0
CIADDR: 0.0.0.0
YIADDR: 0.0.0.0
SIADDR: 0.0.0.0
GIADDR: 0.0.0.0
CHADDR: 00:23:15:5b:a6:60:00:00:00:00:00:00:00:00:00:00
SNAME: .
FNAME: .
OPTION: 53 ( 1) DHCP message type 3 (DHCPREQUEST)
OPTION: 50 ( 4) Request IP address 192.168.1.5
OPTION: 12 ( 5) Host name x201i
OPTION: 55 ( 17) Parameter Request List 1 (Subnet mask)
28 (Broadcast address)
2 (Time offset)
3 (Routers)
15 (Domainname)
6 (DNS server)
119 (Domain Search)
12 (Host name)
44 (NetBIOS name server)
47 (NetBIOS scope)
26 (Interface MTU)
121 (Classless Static Route)
42 (NTP servers)
249 (MSFT - Classless route)
33 (Static route)
252 (MSFT - WinSock Proxy Auto Detect)
17 (Root path)

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^C