리눅스 tcpdump

1 개요

tcpdump
/usr/sbin/tcpdump
TCP덤프, tcpdump 사용법, tcpdump 뜨기

패킷 분석기 소프트웨어
커맨드라인 네트워크 트래픽 모니터링 도구

2 실행예시

eth1 패킷덤프를 파일로 저장

[root@zetawiki ~]# tcpdump -i eth1 -w tcpdump1.pcap
tcpdump: listening on eth1, link-type EN10MB (Ethernet), capture size 65535 bytes
^C75 packets captured
75 packets received by filter
0 packets dropped by kernel

→ Ctrl+C를 눌러 중단하는 시점까지 저장됨

패킷 100개의 덤프

[root@zetawiki ~]# tcpdump -i eth1 -w tcpdump2.pcap -c 100
tcpdump: listening on eth1, link-type EN10MB (Ethernet), capture size 65535 bytes
100 packets captured
100 packets received by filter
0 packets dropped by kernel

pcap 파일 내용 보기

[root@zetawiki ~]# tcpdump -qns 0 -X -r tcpdump1.pcap
reading from file tcpdump1.pcap, link-type EN10MB (Ethernet)
07:23:18.977783 IP 135.145.142.139 > 192.168.0.46: ICMP time exceeded in-transit, length 36
	0x0000:  4500 0038 0000 0000 fb01 72c4 7d91 0ec1  E..8......r.}...
	0x0010:  c0a8 0006 0b00 f4ff 0000 0000 4500 001c  ............E...
	0x0020:  385e 0000 0101 a702 c0a8 0006 72c8 a70a  8^..........r...
	0x0030:  0800 90fd 0001 6701                      ......g.
07:23:18.992044 IP 192.168.0.168.ssh > 192.168.0.46.7929: tcp 132
	0x0000:  4510 00ac dcb3 4000 4006 dc29 c0a8 0008  E.....@.@..)....
	0x0010:  c0a8 0006 0016 1ef9 e662 5e6a d13a 94eb  .........b^j.:..
... (생략)

3 같이 보기

4 참고