Fujitsu ETERNUS DSP Series Cli Reference Manual page 26

2. CLI Commands
tcpdump
verifying the IP and ICMP header checksum. When writing to a file with the -w option, report, every 10 seconds,
the number of packets captured.
-vv Even more verbose output. For example, additional fields are printed from NFS reply packets, and SMB pack-
ets are fully decoded.
-vvv Even more verbose output. For example, telnet SB ... SE options are printed in full. With -X Telnet options
are printed in hex as well.
-w Write the raw packets to file rather than parsing and printing them out. They can later be printed with the -r
option. Standard output is used if file is ``-''. See pcap-savefile(5) for a description of the file format.
-W Used in conjunction with the -C option, this will limit the number of files created to the specified number, and
begin overwriting files from the beginning, thus cre- ating a 'rotating' buffer. In addition, it will name the files
with enough leading 0s to support the maximum number of files, allowing them to sort correctly. Used in con-
junction with the -G option, this will limit the number of rotated dump files that get created, exiting with status 0
when reaching the limit. If used with -C as well, the behavior will result in cyclical files per timeslice.
-x When parsing and printing, in addition to printing the headers of each packet, print the data of each packet
(minus its link level header) in hex. The smaller of the entire packet or snaplen bytes will be printed. Note that
this is the entire link-layer packet, so for link layers that pad (e.g. Ethernet), the padding bytes will also be
printed when the higher layer packet is shorter than the required padding.
-xx When parsing and printing, in addition to printing the headers of each packet, print the data of each packet,
including its link level header, in hex.
-X When parsing and printing, in addition to printing the headers of each packet, print the data of each packet
(minus its link level header) in hex and ASCII. This is very handy for analysing new protocols.
-XX When parsing and printing, in addition to printing the headers of each packet, print the data of each packet,
including its link level header, in hex and ASCII.
-y Set the data link type to use while capturing packets to datalinktype.
-z Used in conjunction with the -C or -G options, this will make tcpdump run " command file " where file is the
savefile being closed after each rotation. For example, specifying -z gzip or -z bzip2 will compress each savefile
using gzip or bzip2. Note that tcpdump will run the command in parallel to the capture, using the lowest priority
so that this doesn't disturb the capture process. And in case you would like to use a command that itself takes
flags or different arguments, you can always write a shell script that will take the savefile name as the only argu-
ment, make the flags & arguments arrangements and execute the command that you want.
-Z Drops privileges (if root) and changes user ID to user and the group ID to the pri- mary group of user. This
behavior can also be enabled by default at compile time.
expression Selects which packets will be dumped. If no expression is given, all packets on the net will be
dumped. Otherwise, only packets for which expression is `true' will be dumped. Expression arguments can be
passed to tcpdump as either a single argument or as multiple arguments, whichever is more convenient.
Generally, if the expression contains Shell metacharacters, it is easier to pass it as a single, quoted argu- ment.
Multiple arguments are concatenated with spaces before being parsed.
26 ETERNUS DSP CLI Reference Guide