Custom Sizing Your MMC RDP Console

Following on from yesterdays post I was looking at some of the options and realised that you actually set the size of you RDP console.Since I use a Mac Book Pro with a wide screen the standard resolution are not very helpful, and I like to have fixed size windows, changing them to use the available width is a good thing™
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Multiple RDP Consoles - Who Knew ?

I have been working with Windows folks for a long time, and I have not seen this tool used before. As a networking guy maybe I missed it.

I often deploy a number of Windows servers to monitor and manage networks (typically with open source and Ciscoworks). I recently discovered the MMC Snap-in for Remote Desktops which makes my life simpler by letting you switch between many consoles at once on a Windows desktop. This is a quick overview on how to configure this for yourself.

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Flush DNS Cache on MAC OS X

Mac OS X - Clearing or flushing the DNS Cache

Once you go to a Web site, or do any DNS lookup, the IP gets cached for quite a while. This becomes a royal pain if you’re a systems administrator who is in the middle of migrating domains from one server to another. Executing the following clears the cache, restarts the caching daemon, and fetches fresh DNS records. And there was much rejoicing…

For Leopard


sudo dscacheutil -flushcache


For Tiger

lookupd -flushcache

(On Windows you do ipconfig /flushdns)

Cisco Application Control Engine (ACE) - Introduction and Comparison With F5

My new interest of the moment is the Cisco Application Control Engine or ACE module. I have just received a pair of them and planning on starting the configuration in the next couple of days. So perhaps some discussion on the ACE is in order, and why I am considering using both F5 LTM AND the Cisco ACE in this network.
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iTerm and Dynamips - Write to All Terminals at Once

I am often find myself needing to stop, make a configuration change to Dynagen, and then restart. To make sure I don’t miss anything I go to every screen and write the configuration.

In iTerm, there is the ability to send the same command to all screens at once, excellent!

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The Balloon Story

Quite some time ago, someone sent me this joke, and to this day, it resonates.

A man piloting a hot air balloon discovers he has wandered off course and is hopelessly lost. He descends to a lower altitude and locates a man down on the ground. He lowers the balloon further and shouts:

“Excuse me, can you tell me where I am?”

The man below says: “Yes, you’re in a hot air balloon, about 30 feet above this field.”

“You must work in Information Technology” says the balloonist.

“Yes I do” replies the man. “And how did you know that?”

“Well” says the balloonist, “what you told me is technically correct, but of no use to anyone.”

The man below says “You must work in Business Management.”

“I do” replies the balloonist with some surprise, “how did you know?”

“Well”, says the IT guy, “you don’t know where you are, or where you’re going, but you expect my immediate help. You’re in a situation that you deliberately created, but now you are expecting me to fix it.”

Suspending and Resuming Dynamips

As someone who travels often, and always looking to make use of the travel time, I was pleased to find that I can suspend and resume the Dynamips routers. This saves me battery on longer trips, or lets me have more CPU when I running other applications such as Parallels / VMware to give me some Microsoft Visio joy. iTerm sessions are not terminated by doing this, they just don’t show any data until you resume the sessions.
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The Poor Man’s IOS Traffic Generator

This is a feature that I used to use years ago, but had forgotten about. For some reason, I remembered it today and it is still as useful as it ever was. Read on…
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Dynamips and the Leopard Terminal

I wanted Dynamips to act more like the way I think and it keeps on opening

gf:~ gregferro$ cd Documents/dynalab/Dynagen/Dynagen.app/Contents/Resources/
gf:Resources gregferro$ ls
AppSettings.plist configobj.pyc dynagen.ini pemu_lib.pyc
appIcon.icns configspec dynamips_lib.py script
confConsole.py console.py dynamips_lib.pyc validate.py
confConsole.pyc console.pyc en.lproj validate.pyc
configobj.py dynagen pemu_lib.py
gf:Resources gregferro$
gf:Resources gregferro$
gf:Resources gregferro$ sudo vim dynagen.ini
Password:

I want to use iTerm instead of the Terminal that is part of Leopard for the Dynagen / dynamips output. So you can see the following

# Uncomment below of OS X with Terminal with named tabs (requires Leopard)
#telnet = /usr/bin/osascript -e 'tell application "System Events" to tell process "Terminal" to keystroke "t" using command down' -e 'tell application "Terminal" to do script with command "telnet %h %p ; exit" in last tab of first window' -e 'tell application "Terminal" to tell window 1 to set custom title to "%d"'

# Uncomment below for OS X with iTerm with named tabs
telnet = /usr/bin/osascript -e 'tell app "iTerm"' -e 'activate' -e 'set myterm to the first terminal' -e 'tell myterm' -e 'set mysession to (make new session at the end of sessions)' -e 'tell mysession' -e 'exec command "telnet %h %p"' -e 'set name to "%d"' -e 'end tell' -e 'end tell' -e 'end tell'

The only problem here is that the Terminal window is still used by Dynagen, so I still end up with Leopard terminal. I wonder if there is a way to fix this.

Configuring iTerm for Dynamips

To get started with my lab faster I use iTerm to prepare a full set of possible sessions. This post walks through how to do this which should help you to get started faster. Also some keyboard shortcuts.
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On Layer 2 Access Designs and MPLS

I looking closely at Data Centre Designs at the moment, and been considering whether a looped triangle or a looped square is the best for edge switches. I find it difficult to detect a difference that makes a clear purchasing decision. So I sat down to think about this. I did some pictures and thinking.
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Unzip IOS Images for Dynamips

I have a directory ‘dynalab’ in my ‘Documents’ where I have put ALL my Dynamips / Dynagen related files. I created a directory there which has all my IOS images, this makes more sense to my mind. Makes it easier to backup.

gf:Documents gregferro$ mkdir dynalab
gf:Documents gregferro$ cd dynalab
gf:dynalab gregferro$ ls
gf:dynalab gregferro$

You can copy IOS images as normal using the Finder into the dynalab directory. To uncompress the images you can either download the Zipeg program (use a search engine to find it), or use the command line as follows:

gf:dyncode gregferro$ unzip -p c1700-sy-121-9.bin > c1700-sy-121-9.image
warning [c1700-sy-121-9.bin]: 16304 extra bytes at beginning or within zipfile
(attempting to process anyway)
gf:dyncode gregferro$


I have renamed the IOS file from .bin to .image so I can determine that it has been uncompressed. I keep the rest of the name the same, because that tells me the feature set of the image.

Now your images are ready to use. You can see the script I use to start Dynamips / Dynagen in a earlier post.

Tips for Dynamips / Dynagen on Leopard OS X

I downloaded the most recent Interim relase from the dynagen.org interim builds web site and then got to work in getting it setup.

To help with the scripting and updates I put everything into a directory under my documents folder called
dynalab
. Then I copied the Dynagen directory from the mounted DMG directly to its own directory.

Then I located some IOS code that I liked the look of, and dropped that into its own directory that I call
dyncode
Then I created a directory called
firstlab
and this is where I have created my lab. The directory looks like this:

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Dynamips on a MacBook Pro

I am doing some proof of concept for an MPLS data centre and did something I have not normally done. I used my MacBook Pro to run Dynamips / Dynagen. I am very pleased with 9 3640 routers running Enterprise Plus, and 2 2611 Routers with IP and running less than 60% CPU across both cores

This means that I have still have enough resources to run quite few other programs including Parallels (although it does run a little slow). I have an older MacBook Pro, but upgraded to to 4 GB RAM. I found that the 2 x 2GB RAM modules run faster than 1 x 2Gb (as you might expect) but its a shame that only 3GB can be used or I could have quite a few more.

I won’t repeat what other people have said about Dynamips, but running it on OS X Leopard is very fine indeed.