Tcpdump

Tcpdump will help you debug network issues by capturing packets from up to 4 individual network interfaces.

Using the Netlog facility, it is possible to copy capture files to a subdirectory, triggered by an error in another log, so the captures before and after the error will be preserved for your analysis.

You can use Wireshark on an external system for analyzing capture files.

Find out more about Tcpdump from its homepage.

IGEL Setup > Registry
> Resolve addresses/ports to names	`debug.tools.tcpdump[0-3].address_resolution`	enabled / disabled

IGEL Setup > Registry
> Compression Method	`debug.tools.tcpdump[0-3].compression`	lzop, gzip, bzip2, xz
The compression method affects file size as well as system performance while compressing. The default lzop methiod is relatively light on the CPU.

IGEL Setup > Registry
> Interface for tcpdump logging	`debug.tools.tcpdump[0-3].interface`	user editable string / eth0
Note: Names `eth0`, `eth1`, `wlan0`, etc. are treated as symbolic names and will internally be replaced by the correct PNINs automatically. For details on PNINs, see LAN Interfaces.

IGEL Setup > Registry
> Number of Rotate Files	`debug.tools.tcpdump[0-3].num_rotate_files`	3 ... 10
Number of files to be kept while rotating.

IGEL Setup > Registry
> Only Log Package Headers	`debug.tools.tcpdump[0-3].only_headers`	enabled / disabled

IGEL Setup > Registry
> Enable promisc tcpdump logging	`debug.tools.tcpdump[0-3].promisc`	enabled / disabled
Enable promiscuous mode on the network interface to also capture packets not intended for this host.

IGEL Setup > Registry
> Logfile rotate size in MiB	`debug.tools.tcpdump[0-3].rotate_size`	10, 15 ,20 ,25 ,30 , 40
Rotate when the size of the uncompressed file reaches this size in MiB.

IGEL Setup > Registry
> Logfile rotate time in s	`debug.tools.tcpdump[0-3].rotate_time`	0 / user editable integer
Time in seconds after which the logfile is rotated and compressed. If set to 0 no time-based rotation happens.

IGEL Setup > Registry
> Additional Parameters for tcpdump	`debug.tools.tcpdump[0-3].tcpdump_additional_parameters`	user editable string
Use with care.

IGEL Setup > Registry
> Enable tcpdump	`debug.tools.tcpdump[0-3].tcpdump_enabled`	enabled / disabled

IGEL Setup > Registry
> tcpdump filter expression	`debug.tools.tcpdump[0-3].tcpdump_filter`	user editable string
Tcpdump filter expression. For the expression syntax, see the pcap-filter(7) manpage.