I am running a Django based http server and I am trying to collect the HTTP headers using tcpdump.
Here is the tcpdump command:
$ sudo tcpdump -i lo0 -s 0 -B 524288 port 8000
and here is the output
19:55:55.388635 IP localhost.irdmi > localhost.50558: Flags [P.], seq 126:8318, ack 602, win 40830, options [nop,nop,TS val 1192418216 ecr 1192418216], length 8192
19:55:55.388649 IP localhost.50558 > localhost.irdmi: Flags [.], ack 8318, win 36734, options [nop,nop,TS val 1192418216 ecr 1192418216], length 0
19:55:55.388657 IP localhost.irdmi > localhost.50558: Flags [P.], seq 8318:16510, ack 602, win 40830, options [nop,nop,TS val 1192418216 ecr 1192418216], length 8192
19:55:55.388666 IP localhost.50558 > localhost.irdmi: Flags [.], ack 16510, win 32638, options [nop,nop,TS val 1192418216 ecr 1192418216], length 0
19:55:55.388673 IP localhost.irdmi > localhost.50558: Flags [P.], seq 16510:24702, ack 602, win 40830, options [nop,nop,TS val 1192418216 ecr 1192418216], length 8192
19:55:55.388682 IP localhost.50558 > localhost.irdmi: Flags [.], ack 24702, win 28542, options [nop,nop,TS val 1192418216 ecr 1192418216], length 0
19:55:55.388687 IP localhost.irdmi > localhost.50558: Flags [.], seq 24702:41034, ack 602, win 40830, options [nop,nop,TS val 1192418216 ecr 1192418216], length 16332
19:55:55.388691 IP localhost.irdmi > localhost.50558: Flags [P.], seq 41034:41086, ack 602, win 40830, options [nop,nop,TS val 1192418216 ecr 1192418216], length 52
19:55:55.388707 IP localhost.50558 > localhost.irdmi: Flags [.], ack 41086, win 20350, options [nop,nop,TS val 1192418216 ecr 1192418216], length 0
19:55:55.388714 IP localhost.irdmi > localhost.50558: Flags [P.], seq 41086:49278, ack 602, win 40830, options [nop,nop,TS val 1192418216 ecr 1192418216], length 8192
19:55:55.388722 IP localhost.50558 > localhost.irdmi: Flags [.], ack 49278, win 16254, options [nop,nop,TS val 1192418216 ecr 1192418216], length 0
19:55:55.388728 IP localhost.irdmi > localhost.50558: Flags [P.], seq 49278:61630, ack 602, win 40830, options [nop,nop,TS val 1192418216 ecr 1192418216], length 12352
19:55:55.388737 IP localhost.50558 > localhost.irdmi: Flags [.], ack 61630, win 10078, options [nop,nop,TS val 1192418216 ecr 1192418216], length 0
Does anybody know what is the problem here? Why cannot I get the full HTTP headers for the request? I tried using wireshark, but I am getting some other errors there.
The command below works for me to grab http headers on port 8000. The -s will grab the first 1024 bytes so you can adjust to grab more or less packet data.
tcpdump -i eth0 -s 1024 -l -A port 8000