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showing posts of August 2018
 
by lunarg on August 24th 2018, at 15:14
In case of disaster, it is usually a very good idea to periodically back up the configuration of your network switches. This article lists syntax for backing up configuration to a TFTP server for different vendors.

In the syntax examples below, the IP for the TFTP is 1.2.3.4, and we're writing to the file switch.cfg.

Note that this article is definitely not complete. If you have additions to this article, please post them in the comments.

The syntax for Dell and Cisco switches is mostly the same. For N-series and PowerConnect, a summary is displayed which needs to be confirmed, which is not the case for Cisco and Dell S-series.

For Cisco Small Business (SF- and SG-series), the CLI ne  ...
by lunarg on August 21st 2018, at 14:44

Cisco's SF/SG 300/500 series managed switches have CLI access via Telnet and SSH but this is turned off by default, leaving only the web interface to manage the switch. You can enable Telnet and/or SSH via the web interface, enabling management via CLI.

  1. Log on to the web interface, then navigate to Security → TCP/UDP Services.
  2. Check the Enable boxes for Telnet Service and/or SSH Service. You can check both if you wish to enable both protocols. Click Apply, which will immediately start the selected services:
  3. Don't forget to save the configuration change to flash. Otherwise, the change will be lost after a reboot:
by lunarg on August 21st 2018, at 14:16
When installing tftpd-hpa, as a security measure, the service does not allow uploading new files. It does allow overwriting existing files, provided that the permissions are set correctly (as expected). The idea behind this is to secure TFTP a bit by only allowing uploads if the file already exists (and is writable). But this can be very tedious in some cases, where a lot of files have to be uploaded, and it is not possible to guess the names to create them in advance.

It is possible to configure tftpd-hpa to allow the creation of new files by adding the -c or --create parameter when starting the daemon.

For Ubuntu and Debian, this means editing the file /etc/default/tftpd-hpa, and adding   ...
by lunarg on August 21st 2018, at 11:20
To enable SSH on Dell Networking N-series (formerly known as Dell PowerConnect), you first have to generate the required private RSA and DSA keys. If you don't, you're met with a very secretive error message:

SSH could not be enabled.

To generate the keys, and configure and enable SSH, log on to the switch using the console cable or log on through Telnet:

Go into EXEC mode, then in CONFIG mode:

enableconfigure

Generate both the RSA and DSA keys:

crypto key generate rsacrypto key generate dsa

Now, you can enable the SSH server:

ip ssh server

Optionally: you can also change the default listen port:

ip ssh port 22

With more recent firmware versions, you are no longer able to   ...
by lunarg on August 16th 2018, at 10:13
MacPostfactor is a tool to install Mac OSX 10.8+ on older Macbooks that normally only support up to OSX 10.7 (Lion). It works through a combination of a highly customized installer, a replaced set of drivers and various frameworks, and the original installation app from the App Store. The installation can be done directly on a Macbook already running OSX Lion (so no USB disk required), or on an USB media for installation on another system.

You need an Intel-based Macbook capable of running OSX Lion (10.7) (otherwise your Mac is too old), but one that does not support OSX Mountain Lion (10.8) or higher. PowerPC-based Macs are not supported (they do not run OSX Lion).

The installer app of th  ...
 
showing posts of August 2018
 
 
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