FreeBSD hang without panic
On a FreeBSD 5.2.1 box that has been in production a long time, I have had a new type of hang on two days this week, the type of which I have not seen before. (No recent software/hardware changes). Symptom: The machine is a web/email server only. It stops receiving new SSH/HTTP/IMAP/POP connections, existing shells cease working. On the machine itself no messages are shown and the machine responds to repeated ENTER key presses with the login prompt. Once you enter root [ENTER] then no further responses (except line feeds as you press ENTER). What kind of hang is this? Could it be a DoS attack? Or is it some internal process hanging? I have a debug kernel but as the only solution is a power-off reset, I never get any dump. Any suggestions please where I might start to look, or services to experiment disabling? __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: What's the best diagnostic utility for wireless signal?
Tim Daneliuk wrote: Andrew Liles wrote: I use wireless on a FreeBSD 6.1 box in an area of low signal to my Access Point. I want to be able to inspect the signal strength/quality so that I may adjust the antenna to get best results. What is the best diagnostic to use? For instance: wicontrol wi0 produces: ... Comms quality/signal/noise: [ 28 47 1 ] dBm Coms Quality: [ 14 -85 -99 ] ... but what is good or which numbers should I be seeking maximise or minimise? Here's a less analytical way that may work if you have marginal signal strength: 1) Connect wirelessly 2) Start pinging a site near you (to mimimize delay effects over the larger internet) 3) Move the antenna around to see where ping delays minimize across Similarly, you can do the same thing with traceroute which is even better because it shows delay at each step of the route. This is a quick-and-dirty scheme that may not always provide best results, but it's easy and a good way to get started For the use of others: By using a graphical meter on a Windows box, I tested different orientations of my Access Point. Empirically I have found: you get this when the Access Point is off: Comms quality/signal/noise:[ 0 0 1 ] dBm Coms Quality:[ 0 -100 -99 ] this is when the signal is poor: Comms quality/signal/noise:[ 14 27 1 ] dBm Coms Quality:[ 7 -91 -99 ] and this when signal is better: Comms quality/signal/noise:[ 52 83 1 ] dBm Coms Quality:[ 26 -73 -99 ] So, in the absence of anything better information, I'd recommend you maximise each of the numbers shown in the above categories shown by the command: wicontrol wi0 Doug points out that these numbers only appear with some drivers - mine is an INTERSIL HFA384x using the wi driver on FreeBSD 6.1 ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
What's the best diagnostic utility for wireless signal?
I use wireless on a FreeBSD 6.1 box in an area of low signal to my Access Point. I want to be able to inspect the signal strength/quality so that I may adjust the antenna to get best results. What is the best diagnostic to use? For instance: wicontrol wi0 produces: ... Comms quality/signal/noise: [ 28 47 1 ] dBm Coms Quality: [ 14 -85 -99 ] ... but what is good or which numbers should I be seeking maximise or minimise? ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
