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promisconlevel: UNIX error - Device busy

New Member

promisconlevel: UNIX error - Device busy

Hi , 

tcpdump is not working (tcpdump -XX -i lan900). Error is :

 tcpdump: recv_ack: promisconlevel: UNIX error - Device busy

i find using promiscuous mode other process, but i didn't found. And i  reinstall tcpdump and reboot server. I didn't fix this. 

my server's version is hp-ux 11.31 

This command ( tcpdump -XX -i lan900 ) working other hp-ux servers.

How do i fix this error ???

Honored Contributor

Re: promisconlevel: UNIX error - Device busy

"lan900" sounds like an aggregate, VLAN or other virtual construct, not a real physical NIC. You might be able to use the promiscuous mode on physical NICs only.

But do you really need promiscuous mode?

If you are trying to get a dump of network traffic that would already be received by your system without promiscuous mode (i.e. either unicast packetss addressed to that system, or broadcast packets) then you don't need promiscuous mode. at all.

If you are trying to diagnose misaddressed packets, multicasts or something more complicated, then you might need promiscuous mode.

If you add the option '-p' to your tcpdump command line, it will skip setting the interface to promiscuous mode and just dump the regular traffic.. For most application-level troubleshooting, that will be enough.