Difference between revisions of "Tcpdump"

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[[Category:Networking]]
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;tcpdump
 
;tcpdump
 
:Trace network traffic, all packets send are reported to standard output (terminal).
 
:Trace network traffic, all packets send are reported to standard output (terminal).
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:::Read packets from <filename>, give absolute time and all data
 
:::Read packets from <filename>, give absolute time and all data
 
;:-n port 53 and ip6 and host <address>
 
;:-n port 53 and ip6 and host <address>
:::1    Do not lookup host or port-names, select only packets from port 53, IPv6 protocol and specified host(address)
+
:::Do not lookup host or port-names, select only packets from port 53, IPv6 protocol and specified host(address)
  
 
In the output Flags are reported that have following meaning:
 
In the output Flags are reported that have following meaning:
<code>
+
S (SYN)
S (SYN),
+
F (FIN)
F (FIN),
+
P (PUSH)
P (PUSH),
+
R (RST),  
R (RST),  
+
U (URG),  
U (URG),  
+
W (ECN CWR),  
W (ECN CWR),  
+
E (ECN-Echo)
E (ECN-Echo)
+
. (ACK)
. (ACK)
+
none if no flags are set...
none if no flags are set...
 

Latest revision as of 15:23, 9 October 2020


tcpdump
Trace network traffic, all packets send are reported to standard output (terminal).
-w <filename> -C 10
Dump raw data to <filename>, create new file after 10 million (not 10MB) bytes are written
-r <filename> -tttt -X
Read packets from <filename>, give absolute time and all data
-n port 53 and ip6 and host <address>
Do not lookup host or port-names, select only packets from port 53, IPv6 protocol and specified host(address)

In the output Flags are reported that have following meaning:

S (SYN)
F (FIN)
P (PUSH)
R (RST), 
U (URG), 
W (ECN CWR), 
E (ECN-Echo)
. (ACK)
none if no flags are set...