I'm trying to capture packets to a file with the -w option but the file is empty yet if I use the '-w -' option to put data on stdout I see plenty of captured packets.
I'm using CentOS 5.5 x86
[root@server ~]# tcpdump -v -i eth0 -w dump -s0
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
718 packets captured
718 packets received by filter
0 packets dropped by kernel
[root@server ~]# file dump
Any ideas why the file is empty?