[Planetlab-users] tcpdump?

[Neil Spring]

On Jul 20, 2005, at 10:42 AM, Ladan Gharai wrote:
> running as root (in my slice) I get:
>
> $ sudo /usr/sbin/tcpdump -i vnet
> Couldn't find user 'pcap'

This problem has been around for a while; I commented on it on the  
support list in May when "lguohan" noticed it.

What appeared to happen was that the tcpdump install in the base  
system was not reliably executing the adduser command in its rpm  
preinstall script.  I speculated that removing and reinstalling  
tcpdump might fix the problem.  (usually, when I'm running tcpdump,  
it's because the machine is screwed up, and running yum is not high  
on my list of things to do when a machine is broken, so I haven't  
tested this approach.)

A smaller fix would be to manually run tcpdump's preinstall script  
within your slice:

/usr/sbin/groupadd -g 77 pcap  2> /dev/null
/usr/sbin/useradd -u 77 -g 77 -s /sbin/nologin -M -r \
     -d /var/arpwatch pcap 2> /dev/null \
     || /usr/bin/chsh pcap /sbin/nologin 2> /dev/null

(beware the bash syntax)

good luck,
-neil