Commands Reference, Volume 3

iptrace Daemon

Purpose

Provides interface-level packet tracing for Internet protocols.

Syntax

/usr/sbin/iptrace [ -a ] [ -b ][ -e ] [ -u ] [ -PProtocol_list ] [ -iInterface ] [ -pPort_list ] [ -sHost [ -b ] ] [ -dHost ] [ -L Log_size ] LogFile

Description

The /usr/sbin/iptrace daemon records Internet packets received from configured interfaces. Command flags provide a filter so that the daemon traces only packets meeting specific criteria. Packets are traced only between the local host on which the iptrace daemon is invoked and the remote host.

If the iptrace process was started from a command line without the System Resource Controller (SRC), it must be stopped with the kill -15 command. The kernel extension loaded by the iptrace daemon remains active in memory if iptrace is stopped any other way.

The LogFile parameter specifies the name of a file to which the results of the iptrace command are sent. To format this file, run the ipreport command. The ipreport command may display the message TRACING DROPPED xxxx PACKETS. This count of dropped packets indicates only the number of packets that the iptrace command was unable to grab because of a large packet, the size of which exceeded the socket-receive buffer size. This message does NOT mean that the packets are being dropped by the system.

Note

The file specified by the LogFile parameter should not reside on an NFS-mounted file system. Specifying an output file on an NFS-mounted file system can cause the iptrace daemon to hang. You may be unable to kill the iptrace daemon if it hangs, requiring that you restart the system.

Flags

-a	Suppresses ARP packets.
-b	Changes the -d or -s flags to bidirectional mode.
-d Host	Records packets headed for the destination host specified by the Host variable. The Host variable can be a host name or an Internet address in dotted-decimal format. If used with the -b flag, the -d flag records packets both going to and coming from the host specified by the Host variable.
-e	Enables promiscuous mode on network adapters that support this function.
-i Interface	Records packets received on the interface specified by the Interface variable.
-L Log_size	This option causes iptrace to log data in such that the `LogFile` is copied to `LogFile.old` at the start and also every time it becomes approximately Log_size bytes long.
-P Protocol_list	Records packets that use the protocol specified by the Protocol_list variable which is a comma separated list of protocols. The Protocols can be a decimal number or name from the /etc/protocols file.
-p Port_list	Records packets that use the port number specified by the Port_list variable which is a comma separated list of ports. The Port_list variable can be a decimal number or name from the /etc/services file.
-s Host	Records packets coming from the source host specified by the Host variable. The Host variable can be a host name or an Internet address in dotted-decimal format. If used with the -b flag, the -s flag records packets both going to and coming from the host specified by the Host variable.
-u	Unloads the kernel extension that was loaded by the iptrace daemon at startup.

Examples

To start the iptrace daemon with the System Resource Controller (SRC), enter:
```
startsrc -s iptrace -a "/tmp/nettrace"
```
To stop the iptrace daemon with SRC enter the following:
```
stopsrc -s iptrace
```
To record packets coming in and going out to any host on every interface, enter the command in the following format:
```
iptrace /tmp/nettrace
```
The recorded packets are received on and sent from the local host. All packet flow between the local host and all other hosts on any interface is recorded. The trace information is placed into the /tmp/nettrace file.
To record packets received on an interface from a specific remote host, enter the command in the following format:
```
iptrace - i en0 -p telnet -s airmail /tmp/telnet.trace
```
The packets to be recorded are received on the en0 interface, from remote hostairmail, over the telnet port. The trace information is placed into the /tmp/telnet.trace file.
To record packets coming in and going out from a specific remote host, enter the command in the following format:
```
iptrace -i en0 -s airmail -b /tmp/telnet.trace
```
The packets to be recorded are received on the en0 interface, from remote hostairmail. The trace information is placed into the /tmp/telnet.trace file.

Related Information

The ipreport command, the tcpdump command.

The /etc/protocols file format, /etc/services file format.