Linuxdoc Linux Questions
Click here to ask our community of linux experts!
Custom Search

7. Trouble Shooting

The servers log file (/var/log/messages) should contain hints as to where you've got to in the boot process, as it should log TFTP transfers, NFS mounts etc. If not, add

*.* /var/log/messages

to

/etc/syslogd.conf

and restart syslog

tcpdump allows you to see what packets are being transfered, and their NFS filenames.

 tcpdump -i eth0 -s 500 host box

Your output from syslog should resemble:

Jul 24 21:37:00 bookcase dhcpd: DHCPDISCOVER from 00:80:64:10:1d:1c via eth0
Jul 24 21:37:00 bookcase dhcpd: DHCPOFFER on 192.168.1.52 to 00:80:64:10:1d:1c    via eth0
Jul 24 21:37:04 bookcase dhcpd: DHCPREQUEST for 192.168.1.52 from 00:80:64:10:1d:1c    via eth0
Jul 24 21:37:04 bookcase dhcpd: DHCPACK on 192.168.1.52 to 00:80:64:10:1d:1c    via eth0
Jul 24 21:37:04 bookcase tftpd[5003]: tftpd: trying to get file: /exports/T1500/tftpboot/vmlinux
Jul 24 21:37:24 bookcase mountd[4853]: authenticated mount request from box:600

Your tcpdump output should look like (when idle):

17:31:41.450000 box.8022008 > bookcase.nfs: 116 lookup fh Unknown/1 "initctl"
17:31:41.450000 bookcase.nfs > box.8022008: reply ok 128 lookup fh Unknown/1

7.1. Intermittent kernel transfer problems (NFS null)

There is a known problem which occasionally causes the T1500 to fail to reboot, apparently because it fails to tftp the kernel after the reboot. A tcpdump of this happening will resemble:

12:04:38.506153 box.2049 > bookcase.house.tftp: 39 RRQ "/exports/T1500/tftpboot/vmlinux"    
12:04:38.556153 bookcase.house.1199 > box.2049: udp 516 
12:04:38.556153 box.2049 > bookcase.house.1199: udp 4 
12:04:38.556153 bookcase.house.196610 > box.nfs: 516 null 
12:04:38.556153 box.2049 > bookcase.house.1199:    udp 4 
12:04:38.556153 bookcase.house.196611 > box.nfs: 516 null 
12:04:38.556153 box.2049 > bookcase.house.1199: udp 4 
12:04:38.556153 bookcase.house.196612 > box.nfs: 516 null 
12:04:38.556153 box.2049 > bookcase.house.1199:    udp 4 
12:04:38.566153 bookcase.house.196613 > box.nfs: 516 null 
12:04:38.566153 box.2049 > bookcase.house.1199: udp 4 
12:04:38.566153 bookcase.house.196614 > box.nfs: 516 null 
12:04:38.566153 box.2049 > bookcase.house.1199:    udp 4 
12:04:38.566153 bookcase.house.196615 > box.nfs: 516 null

You will then see a syslog entry from tftp indicating that it is sending the kernel, but no packets are exchanged. ARP requests go unanswered.

This can be resolved, but if you have your T1500 headless in a corner, is a PITA. Connect a monitor, keyboard and PS/2 mouse if not present. Reboot the T1500, and press 'L' after the 1st beep. The T1500 will now boot locally. Change the boot mode to 'Local' (Start->System menu) and reboot. Change the boot mode back to 'Network'

If this happens to you a lot, please try out tiggers-magic-tftpd. You can find this at the same URL this document gives as the current home of the T1500 HOWTO. It requires python, and has been reported to solve the problem. Please let me know how you get on !

7.2. T1500 ignores DHCP OFFER and just asks again

There is a bug in the BIOS, all DHCP packets must contain a 'root-path' option, even if you are booting your own kernel which doesn't need one.