tcpdump to SD card

[zubr]

Hi,

I want to write the output of tcpdump to my external SD card.

The external SD card is on filesystem /dev/sdcard/sd1 and mounted to /sd (this is what Infusion Resources says).

So as command for tcpdump I used

tcpdump -w /sd/tcpdump.pcap

but the output is not written to that SD card but to rootsfs (which has a very limited space of 3,3MB).

So how can I manage tcpdump to write to the external SD card?

Thank you.

Chris

[sud0nick]

I'm not 100% certain on this but according to this site https://www.wireshark.org/docs/wsug_html_chunked/AppToolstcpdump.html you have to specify both an interface AND a file in order to save output. It's worth a shot.

[DataHead]

follow these steps

cd /sd

tcpdump -w ./tcpdump.pcap

if you cd /sd first, it changes the working directory. the "./" means the current working directory, so it will save the log to /sd/tcpdump.pcap

tested it and it works as expected

[zubr]

Thank you, the way with "cd /sd" worked.