July 17, 2014

A very short post about 802.1x (dot1x) on Cisco Catalyst 2950 series. Configure RADIUS and enable dot1x on the switch: aaa authentication dot1x default group radius aaa accounting dot1x default start-stop group radius dot1x system-auth-control Then enable dot1x on all interfaces (additional security commands are added in the example below):

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March 06, 2014

My Internet connection is cheap enough and a little bit crappy. Cisco provides Embedded Event Manager (EEM), useful to manage a situation like mine: event manager applet RESTART_ATM event interface name "ATM0" parameter input_errors_crc entry-val 3000 entry-op gt entry-val-is-increment true exit-comb or exit-val 1 exit-op le exit-val-is-increment true exit-time 5 poll-interval 3600 maxrun 10 action 1.

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February 24, 2014

OpenSSH allows SSH/SFTP users to connect to the whole system by default. In many cases this is not the expected behavior: users should be relegated to the home their home directory only.

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February 03, 2014

In last Cisco Live 2014 (Milan) there was a lab on Cisco VIRL/CML. Only one PC located in the Walk-in-lab room was available to start a VIRL lab, and I couldn’t miss that chance to see what exactly VIRL is.

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September 12, 2013

TFTP or Trivial File Transfer Protocol is a simple file transfer protocol. TFTP uses UDP port 69, no authentication or encryption is supported, and directory navigation is not possible. Three file transfer methods are available: netascii (or ASCII for text files), octet (or image for binary files), and mail (not used anymore).

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August 27, 2013

The Cisco WAAS system consists of a set of devices that work together to optimize TCP network traffic. There are two types of devices that run WAAS software: Cisco Wide Area Application Engine (WAE) Cisco Wide Area Virtualization Engine (WAVE) WAVE appliances implement virtualization: virtual blades can run one or more virtualized OSes within the WAVE appliance.

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August 12, 2013

I replaced most of my Bash script with Python but sometimes I still need Bash. The following script requires uuencode and sends an email with attachments using Bash: #!/bin/bash PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin" EMAIL_OK="dainese@example.

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May 24, 2013

This article will show a list of activities to basically configure a Cisco Nexus 5000 switch. This is not an advanced configuration article, just an overview of basic configuration. People new to Cisco Nexus switches will be displaced by three features/commands:

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May 10, 2012

In this post we’ll see how to shrink a virtual (VMDK) disk before releasing the OVF/OVA image. Developing a VM which will be distributed online, require saving space. After deleting cache, log files, and so on, vmdk files won’t become smaller.

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