File Transfers

Downloading Switch Software

authorized_keys \---oper_keys

authorized_keys

■When using SFTP to copy a software image onto the switch, the command return takes only a few seconds. However, this does not mean that the transfer is complete, because the switch requires additional time (typi- cally more than one minute) to write the image to flash in the background. To verify the file transfer has been completed, you can use the show flash command or look for a confirmation message in the log as in the following example:

I 01/09/09 16:17:07 00150 update: Primary Image updated.

Once you have configured your switch to enable secure file transfers with SCP and SFTP, files can be copied to or from the switch in a secure (encrypted) environment and TFTP is no longer necessary.

 

Troubleshooting SSH, SFTP, and SCP Operations

 

You can verify secure file transfer operations by checking the switch’s event

 

log, or by viewing the error messages sent by the switch that most SCP and

 

SFTP clients will print out on their console.

 

 

N o t e

Messages that are sent by the switch to the client depend on the client software

 

in use to display them on the user console.

 

Broken SSH Connection. If an ssh connection is broken at the wrong

 

 

moment (for instance, the link goes away or spanning tree brings down the

 

link), a fatal exception would occur on the switch. If this happens, the switch

 

will gracefully exit the session and produce an event log message indicating

 

the cause of failure. The following three examples show the error messages

 

that may appear in the log depending on the type of session that is running

 

(SSH, SCP, or SFTP).

 

ssh: read error Bad file number, session aborted I 01/

 

01/90 00:06:11 00636 ssh: sftp session from

 

::ffff:10.0.12.35 W 01/01/90 00:06:26 00641 ssh:

 

sftp read error Bad file number, session aborted I 01/

 

01/90 00:09:54 00637 ssh: scp session from

 

::ffff:10.0.12.35 W 01/01/90

 

ssh: scp read error Bad file number, session aborted

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