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Diffstat (limited to 'Documentation/networking/netconsole.txt')
-rw-r--r-- | Documentation/networking/netconsole.txt | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/Documentation/networking/netconsole.txt b/Documentation/networking/netconsole.txt new file mode 100644 index 000000000000..53618fb1a717 --- /dev/null +++ b/Documentation/networking/netconsole.txt @@ -0,0 +1,57 @@ + +started by Ingo Molnar <mingo@redhat.com>, 2001.09.17 +2.6 port and netpoll api by Matt Mackall <mpm@selenic.com>, Sep 9 2003 + +Please send bug reports to Matt Mackall <mpm@selenic.com> + +This module logs kernel printk messages over UDP allowing debugging of +problem where disk logging fails and serial consoles are impractical. + +It can be used either built-in or as a module. As a built-in, +netconsole initializes immediately after NIC cards and will bring up +the specified interface as soon as possible. While this doesn't allow +capture of early kernel panics, it does capture most of the boot +process. + +It takes a string configuration parameter "netconsole" in the +following format: + + netconsole=[src-port]@[src-ip]/[<dev>],[tgt-port]@<tgt-ip>/[tgt-macaddr] + + where + src-port source for UDP packets (defaults to 6665) + src-ip source IP to use (interface address) + dev network interface (eth0) + tgt-port port for logging agent (6666) + tgt-ip IP address for logging agent + tgt-macaddr ethernet MAC address for logging agent (broadcast) + +Examples: + + linux netconsole=4444@10.0.0.1/eth1,9353@10.0.0.2/12:34:56:78:9a:bc + + or + + insmod netconsole netconsole=@/,@10.0.0.2/ + +Built-in netconsole starts immediately after the TCP stack is +initialized and attempts to bring up the supplied dev at the supplied +address. + +The remote host can run either 'netcat -u -l -p <port>' or syslogd. + +WARNING: the default target ethernet setting uses the broadcast +ethernet address to send packets, which can cause increased load on +other systems on the same ethernet segment. + +NOTE: the network device (eth1 in the above case) can run any kind +of other network traffic, netconsole is not intrusive. Netconsole +might cause slight delays in other traffic if the volume of kernel +messages is high, but should have no other impact. + +Netconsole was designed to be as instantaneous as possible, to +enable the logging of even the most critical kernel bugs. It works +from IRQ contexts as well, and does not enable interrupts while +sending packets. Due to these unique needs, configuration can not +be more automatic, and some fundamental limitations will remain: +only IP networks, UDP packets and ethernet devices are supported. |