CODEWITHSUNDEEP
network-programmingnetwork-protocolstcpdump
Udit Gupta
Udit Gupta

Reputation: 3272

How to find out the correct packet length?

I am sending three types of packets on another machine in LAN using SENDIP tool I have specified min. length = 8 bytes and max.length = 512 bytes...

but....

when I send udp packets (min. length) and capture using tcpdump it shows pointer length=70 bytes.

when I send udp packets (min. length) tcpdump shows pointer length=574 bytes.

when I send icmp packets (min length),tcpdump shows length of first two packets as 80 and length of rest all packets as 66 bytes.

The pointer length I am getting through tcpdump is by using header information specified in the packet....

Why there is discrepancy between the results of sendip and tcpdump ???

Upvotes: 0

Views: 3077

Answers (1)

CrackerJack9
CrackerJack9

Reputation: 3651

Use the -s 0 option when running tcpdump. This will cause it to capture the entire frame.

Upvotes: 1

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