Eu nunca usei iptraf, mas vamos lá:
você pode checar logs e sockets pra ver se não está gerando conflitofacility already running/listening on interface
The facility you tried to start is currently running on the indicated interface in another IPTraf process on the machine. This restriction is placed to prevent conflicts involving internal sockets or the log files.
você também pode tacar um FORCE, mas não faço idéia das repercurssões pois nunca usei iptraf
IPTraf's internal behavior does not allow its facilities to work well with other instances of themselves. To prevent conflicts involving internal resources (sockets) or files (logs), IPTraf will not allow more than one instance of a facility (traffic monitor, interface statistics, etc) to run at the same time. However, multiple copies of IPTraf can be started, each running a different facility. Configuration is only allowed for the first instance of IPTraf, subsequent instances cannot modify the configuration.
The -f parameter overrides the existing tags attached to the IPTraf process and to the various facilities, causing this instance to think it is the first and that there are no other facilities running. Use this parameter with great caution. A common use for this parameter is to recover from abrupt or abnormal terminations which may leave stale tags still lying around.
The -f parameter may be used together with the others.