List of undocumented tags that can be used in Universal Device Templates (UDT) and Universal Line Templates (ULT)




network-clock synchronization automatic
controller T1 0/1/0
clock source line primary
network-clock input-source 1 controller T1 0/1/0
show commands

clear counters
sh network-clocks synchronization
sh control t1 0/1/0

Common CUCM LDAP Filter Examples:

Example 1 – Account Enabled and ipPhone field populated

(& (objectclass=user)(!(objectclass=Computer))(!(UserAccountControl:1.2.840.113556.1.4.803:=2))(ipPhone=*))

Example 2 – Account Enabled and ipPhone field with entry starting with 22

(& (objectclass=user)(!(objectclass=Computer))(!(UserAccountControl:1.2.840.113556.1.4.803:=2))(ipPhone=22*))


Redirect a small part of the config to a file in flash and replace the config with the small config snippet.

yourname#show run int g0/1 | redirect flash:clean
yourname#configure replace flash:clean


At this time, IOU is my emulator of choice. It is very light weight, has routing and switching emulators and will be the basis for the new CCIE R&S Lab. That being said, it is a pain to get running the first time. It is not as easy as GNS3. This is a short copy/paste tutorial to help install IOU on Ubuntu 14.04.


While working at an ISP for two years, I often needed to give technicians a script with a standard config and instructions to change variables. I started with simple text files, then custom php scripts and finally worked with a friend to create


‘Screen’ is an application built into Linux and Unix based platforms that allows you to manage multiple windows within a single ssh session. However, it can also be used as a terminal for a USB to serial adapter.


I ran into a strange issue today while building my new IOU virtual lab. After firing up the lab script and, I was able to see cdp neighbors with other devices in the network and even OSPF errors. However, I was not able to ping or connect to my lab router’s ethernet interface. The problem was VSphere rejecting promiscuous mode by default.

In the VSphere Client
VMWare Host > Configuration > Networking > vSwitch Properties

In the vSwitch Properties
Security Tab > Check ‘Promiscuous Mode’ and select ‘Accept’

Many people use sites like or to identify the public IP address of an unfamiliar network.

Telnet to or if you do not have a web browser (router, switch, linux).
Note: the original domain name was but it has not worked for a while.

[josh@webserver ~]$ telnet
Connected to
Escape character is ‘^]’.
This is the telnet autoresponder at
You have connected over IPv4.
Your IP address is
Connection closed by foreign host.

As most of you may or may not know, Cisco currently only provides non-bootable Unified Communications ISO images on CCO for download. These ISOs are listed as being provided for “upgrades” and hence will not boot.
The only difference between these non-bootable images and a bootable disc is that the bootable disc includes a boot sector file.   Fortunately, this boot sector file can easily be extracted from a bootable disc and then injected into your non-bootable ISO.  To accomplish this, you will need to use some sort of ISO image software such as UltraISO, MagicISO, PowerISO, etc.  I prefer to use UltraISO for its ease of use.

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