dmesg not providing useful info
 

when I enter dmesg | grep foo in a terminal I get nil output.

If I enter dmesg on it's own, I get a stream like the last few lines listed below:

Shorewall:net2fw:DROP:IN=eth0 OUT= MAC=00:14:85:1f:2c:57:00:1b:11:0d:83:27:08:00 SRC=10.1.1.1 DST=10.1.1.3 LEN=407 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=2050 DPT=1730 LEN=387
Shorewall:net2fw:DROP:IN=eth0 OUT= MAC=00:14:85:1f:2c:57:00:1b:11:0d:83:27:08:00 SRC=10.1.1.1 DST=10.1.1.3 LEN=401 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=2050 DPT=1730 LEN=381
Shorewall:net2fw:DROP:IN=eth0 OUT= MAC=00:14:85:1f:2c:57:00:1b:11:0d:83:27:08:00 SRC=10.1.1.1 DST=10.1.1.3 LEN=401 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=2050 DPT=1730 LEN=381

Why is this, and what do I need to do to restore dmesg output to display settings???

Hi Johng, What do you want to look for? isn't foo an alias?

Iptables (shorewall) outputs in realtime to the terminal.

I think you can change this behaviour (path) to a different screen, but I'm not sure atm.

On my system I can see it on ctrl+alt+F12.

regards Glenn

dmesg merely shows the (kernel) ring buffer - it it has rolled around, maybe the data you are looking for has been lost. Perhaps you should see what is actually in it (using less say), and if Shorewall is writing so much as to purge everything else, change the Shorewall config.

Thank you GlennsPref and syg00

The foo in 'dmesg | grep foo' was intended to indicate the likes of dmesg | grep ivtv, etc.

I tried changing this line in shorewall.conf without effect:

"LOGFILE=/var/log/messages" to "LOGFILE=/var/log/shorewall #messages"

Stopping shorewall stopped shorewall cluttering dmesg, but it is still being cluttered by network messages like this:

DROPPED IN= OUT=eth0 SRC=10.1.1.3 DST=224.0.0.22 LEN=48 TOS=0x00 PREC=0xC0 TTL=1 ID=0 DF OPT (94040000) PROTO=2
DROPPED IN=eth0 OUT= MAC= SRC=10.1.1.3 DST=239.255.255.250 LEN=122 TOS=0x00 PREC=0x00 TTL=1 ID=0 DF PROTO=UDP SPT=2596 DPT=1900 LEN=102

You might ask why it matters? It matters when you're trying to debug something like a usb TV device.

So the question remains, how do I stop or divert the shorewall and network (if that's what it is) from purging everything else?