Cisco 6506 recovery

Last night I did the bare metal recovery of a Cisco 6506 that we salvaged from an old company. I got two systems, one of them I had some trouble with, and ultimately wouldn't boot and complain about the backplane.

Trying to fix the problem, I accidentally deleted the good firmware image and the system wouldn't even boot anymore, stuck at the ROMMON prompt.

So to recovery a system from the ROMMON prompt, there's a quick way to work. Quick being a relative word, considering it still means easily half an hour to 40 minutes of work.

So, from there you just have to push a new image to memory using a serial cable. Needless to say, this is time consuming.

What I did was run the 'xmodem -cys 38400' command, put minicom from the 9600 speed to 38400, and fire away a new firmware image (CatOS 5-4-3 actually). The benefit of running xmodem with the -y and -s 38400 switches are increased speed as compared to standard xmodem (because you tell it to use the enhanced ymodem protocol) which would be forced to run at the standard console speed of 9600 for this type of system.

As an example, pushing the CatOS 5.4(3) image took roughly 30 minutes at 38400 bps. We'd be talking about easily 2 to 3 hours using 9600bps.

Once that was done, failed the first time because of bad CRC, redone, and redone a couple more times, I finally got it right: I was able to boot into a workable system, adjust configuration and download a good new image onto bootflash. Et voila, no more backplace issues, no more booting problems.

The next step will be to fix the attached MSFC1 to the SUP1A I currently have, which still refuses to boot. This is fairly straightforward, considering it's again getting into a ROMMON state, then downloading a new image for the MSFC1.

Thanks Cisco for this nice little ymodem feature, and the good documentation about recovery procedures. This was a cheap, but still really heavy and loud paperweight I had before I pushed a new configuration.

Two useful network-related commands

mtrudel@laptopl-mtrudel:~$ sudo ethtool eth0
[sudo] password for mtrudel:
Settings for eth0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pumbag
Wake-on: g
Current message level: 0x00000001 (1)
Link detected: yes

ethtool is a command that gives you information on the capabilities of your network card, and the network that it is connected to. The most interesting things are the Speed and Duplex lines, which are somewhat useful when diagnosing some very specific problems. Some people may already know of mii-tool which is also available on default installs of ubuntu, however, you should know that mii-tool doesn't support Gigabit ethernet, and as such may give you weird results in that case. ethtool, on the other hand, works fine on gig.

Another cool command I found out about recently, is an implementation of a CDP listener on linux: cdpr. cdpr is available with a simple sudo apt-get install cdpr. cdpr listens for CDP advertisements coming from Cisco hardware, which will let you know what switch you are connected to, some additional information about the switch, and more importantly, which port you are connected in. That's pretty neat for large offices, especially if you're not sure where all the wired are going, and which is which when in a wiring cabinet. To use cdpr:

mtrudel@laptopl-mtrudel:~$ sudo cdpr
cdpr - Cisco Discovery Protocol Reporter
Version 2.2.1
Copyright (c) 2002-2006 - MonkeyMental.com

1. eth0 (No description available)
2. tun0 (No description available)
3. any (Pseudo-device that captures on all interfaces)
4. lo (No description available)
Enter the interface number (1-4):1
Using Device: eth0
Warning opening device (arptype 65534 not supported by libpcap - falling back to cooked socket)
Waiting for CDP advertisement:
(default config is to transmit CDP packets every 60 seconds)
Device ID
value: switch4529
Addresses
value: 192.168.45.29
Port ID
value: FastEthernet0/33

Now I'd just need to walk over to that switch to do whatever I may need to do directly on it... or telnet, ssh, or point a browser to it if I needed to change the configuration.