tcpdump error: no suitable device found

zampya · May 17, 2004, 4:29pm

Hi,

I'm trying to use tcpdump for the first time. I installed tcpdump from the rpm. Now when I issue the command tcpdump port 6666, I get an error

tcpdump: no suitable device found

Can you tell me what's wrong there?

Thanks.

zazzybob · May 17, 2004, 4:31pm

You need to run tcpdump as root. Same goes with tools that depend on it such as ethereal and ngrep.

Peace,
ZB
http://www.zazzybob.com

zampya · May 17, 2004, 4:35pm

I was the root on this occasion.

Thanks.

zazzybob · May 17, 2004, 4:38pm

Which OS are you using??

Under some OSs (BSD, Solaris) you must have read access to the /dev/bpf* devices.

Peace,
ZB
http://www.zazzybob.com

zampya · May 17, 2004, 4:41pm

It's Linux on i686.

Please detail the procedure I have to do.

Thanks.

zazzybob · May 17, 2004, 4:46pm

If your OS is Linux, try tcpdump -i eth0 dst port 6666 This will show you traffic heading towards port 6666. Conversly tcpdump -i eth0 src port 6666 shows traffic heading out of port 6666. man tcpdump should provide the answers.

Try tcpdump -i eth0 should dump all traffic.

Cheers
ZB