Commands using tcpdump (52)
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1tcpdump -ntr NAME_OF_CAPTURED_FILE.pcap 'tcp[13] = 0x02 and dst port 80' | awk '{print $4}' | tr . ' ' | awk '{print $1"."$2"."$3"."$4}' | sort | uniq -c | awk ' {print $2 "\t" $1 }'
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then open with wireshark
1tcpdump src <srcIP> and dst <dstIP> -w file.pcap -
1tcpdump -i eth0 port http or port smtp or port imap or port pop3 -l -A | egrep -i 'pass=|pwd=|log=|login=|user=|username=|pw=|passw=|passwd=|password=|pass:|user:|userna me:|password:|login:|pass |user '
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NOTE: When opening the files you might need to strip the very top line with notepad++ as its a mistake header This is useful when the local machine where you need to do the packet capture with tcpdump doesn?t have enough room to save the file, where as your remote host does tcpdump -i eth0 -w - | ssh forge.remotehost.com -c arcfour,blowfish-cbc -C -p 50005 "cat - | gzip > /tmp/eth0.pcap.gz" Your @ PC1 doing a tcpdump of PC1s eth0 interface and its going to save the output @ PC2 who is called save.location.com to a file /tmp/eth0-to-me.pcap.gz again on PC2 More info @: http://www.kossboss.com/linuxtcpdump1 Show Sample Output
1tcpdump -i eth0 -w - | ssh forge.remotehost.com -c arcfour,blowfish-cbc -C -p 50005 "cat - | gzip > /tmp/eth0.pcap.gz" -
1tcpdump host <IP> -nXXv -s0 -w file.pcap
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capture 2000 packets and print the top 10 talkers
1tcpdump -tnn -c 2000 -i eth0 | awk -F "." '{print $1"."$2"."$3"."$4}' | sort | uniq -c | sort -nr | awk ' $1 > 10 ' -
1tcpdump -nnvvXSs 1514 -i <device> <filters>
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0sniff_host: tcpdump -nn -i eth1 -w - | nc 192.168.0.2 666
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0tcpdump -i any -n tcp[13] == 2
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You don't need this command often and there are other ways to test output but if you want to be sure if your router and ethernet card are working this is one way. Show Sample Output
0sudo tcpdump -i eth0 -n port 67 and 68 -
The command is useful for monitoring the use of the boxes and their connection IP. Result file "sniff" is readable with GUI program "wireshark" or through CLI with the command: tcpdump -f "sniff" -XX Show Sample Output
0tcpdump -i eth0 "tcp port pop3 and ip[40] = 85 and ip[41] = 83" -s 1500 -n -w "sniff" -
The tcpdump arguments are just an example.
0tcpdump -w "$(sed 's/-//gi; s/ /_/gi'<<<"-vvv -s0 -ieth1 -c10 icmp").pcap" -
analyze traffic remotely over ssh w/ wireshark When using tcpdump, specify -U option to prevent buffering and -iany to see all interfaces. Show Sample Output
0ssh root@HOST tcpdump -iany -U -s0 -w - 'not port 22' | wireshark -k -i - -
0sudo tcpdump -n -i eth0 -w data.pcap -v tcp or udp and 'not host 192.168.1.2'
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Sometimes it is useful to have just a general picture of "what is taking all the bandwidth here". Running this command will limit tcpdump to a few packets (instead of flooding your terminal endlessly) and will provide a small, but sometimes sufficient, sample to determine what is going on. Useful to quickly diagnose DOS attacks.
0tcpdump -i eth0 -n | head -
Where src or dst is the host that you want to view the HTTP header.
0tcpdump -s 1024 -l -A src 192.168.9.56 or dst 192.168.9.56 -
0tcpdump -i eth0 -s 65535 -w test_capture
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This is useful when the local machine where you need to do the packet capture with tcpdump doesn?t have enough room to save the file, where as your remote host does tcpdump -i eth0 -w - | ssh savelocation.com -c arcfour,blowfish-cbc -C -p 50005 "cat - > /tmp/eth0.pcap" Your @ PC1 doing a tcpdump of PC1s eth0 interface and its going to save the output @ PC2 who is called save.location.com to a file /tmp/ppp1-to-me.pcap.gz again on PC2 More info @: http://www.kossboss.com/linuxtcpdump1 Show Sample Output
0tcpdump -i eth0 -w - | ssh savelocation.com -c arcfour,blowfish-cbc -C -p 50005 "cat - > /tmp/eth0.pcap" -
0tcpdump -nvvX -s 768 src x.x.x.x and dst port 80
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Human readable representation of the headers of an ICAP request, using tcpdump Show Sample Output
0tcpdump -A -s 10240 'tcp port 1344 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | egrep --line-buffered "^........(REQMOD |RESPMOD )|^[A-Za-z0-9-]+: " | sed -r 's/^........(REQMOD |RESPMOD )/\n\1/g' -
capture trafic for wireshark from spesific eth interface Show Sample Output
0tcpdump -i eth1 -s0 -v -w /tmp/capture.pcap -
tcpdump into file with date format for wireshark Show Sample Output
0tcpdump -i eth1 -s0 -v -w /tmp/capture_`date +%d_%m_%Y__%H_%I_%S`.pcap -
0tcpdump -nqt -s 0 -A -i eth0 port 5060
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0sudo tcpdump -i lo -nv ip
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This is a better way to do the "src X or dst X" filter; plus you might not want to bother with DNS lookups (-n).
-1tcpdump -s 1024 -l -A -n host 192.168.9.56 - < 1 2 3 >
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