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March 30, 2011

Unlocking CISCO devices to work with “unsupported” SFP

Filed under: Uncategorized — Tags: , , — admin @ 1:41 pm

In cisco equipment there is one very irritating problem – it works only with “cisco” SFPs.

Well actually cisco is not manufacturing sfps so basically there is just some check going on inside the router/switch. It can drive you crazy if your only cisco sfp dies and you have nothing except for some normal 3rd party sfp (which is by cisco standard not compatible).

Well there is a way how to go around this. In ios command line write the following :

service unsupported-transceiver

This will cause this to come up your screen:

Warning: When Cisco determines that a fault or defect can be traced to
the use of third-party transceivers installed by a customer or reseller,
then, at Cisco’s discretion, Cisco may withhold support under warranty or
a Cisco support program. In the course of providing support for a Cisco
networking product Cisco may require that the end user install Cisco
transceivers if Cisco determines that removing third-party parts will
assist Cisco in diagnosing the cause of a support issue.

if that did not scared you off just continue with the following:

no errdisable detect cause gbic-invalid

There are some cases that the sfp is not working properly but the odds are something like 100:1

As a side note Huawei equipment does not block any vendor’s sfp but has also list of supported modules which is rather to good idea to read because the “non-supported” sfps have usually some issues.


March 15, 2011

copy partition with dd

Filed under: Linux — Tags: — admin @ 6:28 pm

HDD or partition backup with dd
full hard disk copy

dd if=/dev/sdx of=/dev/hdy
dd if=/dev/sdx of=/path/to/image
dd if=/dev/sdx | gzip > /path/to/image.gz

sdx could be sda, sdb etc. In the second example gzip is used to compress the image if it is really just a backup.

Restore Backup of hard disk copy

dd if=/path/to/image of=/dev/sdx
gzip -dc /path/to/image.gz | dd of=/dev/sdx

Getting around file size limitations using split
When making images, it’s quite easy to run up against various file size limitations. One way to work around a given file size limitation is to use the split command.

# dd if=/dev/sda1 | gzip -c | split -b 2000m – /mnt/sdc1/backup.img.gz.
This example is using dd to take an image of the first partition on the first harddrive.
The results are passed through to gzip for compression
The -c option switch is used to output the result to stdout.
The compressed image is then piped to the split tool
The -b 2000m switch tells split how big to make the individual files. You can use k and m to tell switch kilobytes and megabytes (this option uses bytes by default).
The – option tells split to read from stdin. Otherwise, split would interpret the /mnt/hdc1… as the file to be split.
The /mnt/hdc1… is the prefix for the created files. Split will create files named backup.img.gz.aa, backup.img.gz.ab, etc.
To restore the multi-file backup, do the following:

# cat /mnt/sdc1/backup.img.gz.* | gzip -dc | dd of=/dev/sda1
Cat recombines contents of the compressed and split image files to stdout, in order.
Results are piped through gzip for decompression.
And are then written to the first partition of the hard drive with dd.

check subnet reverse

Filed under: Linux — admin @ 6:26 pm

[root@home ~]# dig @ -x ns +noall +authority;

; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_5.3 <<>> @ -x ns +noall +authority
; (1 server found)
;; global options: printcmd 1800 IN SOA 2007020501 28800 7200 2678400 1800

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