December 2018
Beginner
826 pages
22h 54m
English
Content preview from Linux Administration Cookbook
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tcpdump
Another tool we've used before is tcpdump; it prints and saves network traffic for debugging later or in the moment:
$ sudo tcpdump not port 22tcpdump: verbose output suppressed, use -v or -vv for full protocol decodelistening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes15:26:48.864239 IP centos1 > server-54-230-129-152.ams50.r.cloudfront.net: ICMP echo request, id 3927, seq 284, length 6415:26:48.866009 IP centos1.46283 > 10.0.2.3.domain: 32699+ PTR? 152.129.230.54.in-addr.arpa. (45)15:26:48.899019 IP 10.0.2.3.domain > centos1.46283: 32699 1/0/0 PTR server-54-230-129-152.ams50.r.cloudfront.net. (103)15:26:48.899678 IP centos1.44944 > 10.0.2.3.domain: 7093+ PTR? 15.2.0.10.in-addr.arpa. (40)15:26:48.900853 IP 10.0.2.3.domain ...