Author Archive

SSH command for MAC OS X terminal app

Are you used to just pulling up Putty every time you need to SSH into a switch, router or server, but now you are using a MAC? Me too! Since I have switched to a Macbook Pro as my primary device from time to time I have needed to quickly access network gear via SSH instead of clear text Telnet and needed a quick solution. Sure I have SecureCRT and it is definitely my favorite terminal emulator hands down especially since they added tabs just like you are used to seeing in Chrome or FireFox! Here is a link to it if you have never used or heard of it It isn’t free but most things worth using aren’t in my opinion 🙂

Why not use some other program or free app you ask to replace Putty? Because I love the look and feel of the built-in terminal app that comes with MAC OS X. Also my favorite window setting is “Pro” It is a transparent command prompt type window that you can see the text in the window behind it. It is really great for needing to reference previous code or Cisco how to articles and not have to open and close windows continuously. Also of course I have Parallels loaded for mainly ADUC tasks only and yes Putty is installed on there in case all else fails. But I doubt that is going to happen. Last but not least if you have SecureCRT why do you need to use another app? Sometimes I need multiple windows instead of tabs and terminal is quick and easy. I also wanted to help point other Network Engineers/Admins/Analysts/Techs in the right direction to use a free built-in app that comes with MAC OS X!

Anyway here is a short and quick command to type into the terminal program on your MAC OS X:

user$ ssh -l “username” “IPAddress”


ssh -l admin

Immediately you should be prompted to enter in a password on the next line if SSH is enabled on the device you are trying to access and you have the correct IP Address. And that -l up above is a lower case “L”

Stay tuned for more and more how to articles to come including a lot on Cisco CCNP Routing & Switching material!

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How to track down which switch port a device is connected to on a Cisco switch

How to track down a computer, printer, network node etc.. by using only it’s MAC Address:

Telnet/SSH into your Layer 3 Core switch or router device on your LAN:

L3Core#sh mac address-table

Find the mac address you are looking for like this one:

100 0000.0000.0000 dynamic ip,ipx,assigned,other TenGigabitEthernet1/1/12

Then type in “show cdp neighbor” to see which switch/router is connected to TenGigabitEthernet1/1/12. It’s whatever the next hop is and is most likely a trunk port:

L3Core#sh cdp neighbor

Output –> Cisco-3548-Closet Ten 1/1/12 147 T S Cisco-3548-Closet- Gig 0/1 (<– This output tells me that it is going out Gig0/1 which is also a trunk/uplink port to another switch)

Then telnet/ssh into the next 3548 Cisco switch or whatever switch this is connected to and run this command:

Cisco-3548-Closet2#sh mac address address 0000.0000.0000 (<– whatever the mac address is of the device you are trying to find. In my example I use all 0's)

You will see then see the output of what port that it is connected to:

Cisco-3548-Closet2#sh mac address address 0000.0000.0000
Mac Address Table

Vlan Mac Address Type Ports
—- ———– ——– —–
100 0000.0000.0000 DYNAMIC Gi0/47
Total Mac Addresses for this criterion: 1

If you then study the output above you can see that MAC Address 0000.0000.0000 is going out of port 47 on the Closet2 Switch. If you then trace that port to the patch panel and back to the port on the wall that is labeled with that patch panel port # then you will now know where and what device belongs to that MAC Address!

It is a long process if you don't have but one layer 3 device (because L2 doesn't know IP addresses only MAC Addresses, useful if you have the IP) because of course your layer 3 device that is handling all of the routing will tell you its going out its trunk port to the next hop unless of course its connected directly to the core router/switch that most of the time houses fiber connections back to communication closets where all the layer 2 switches reside.

Please take note above in the last command entered that you have to enter in the word "address" twice on some older Cisco gear. Not sure if newer IOS's have it changed or not…

So in conclusion sometimes it takes a few steps to track down a specific MAC and or IP Address on the network but it can be done fairly quickly when you get used to the commands above. On large enterprise networks with thousands of switch ports these commands are very useful when your System Admins, DBA's, Tech's etc.. ask you what port on the network is such and such device plugged into. You can now smile, load up your favorite terminal emulation program like Putty, SuperPutty, my personal favorite SecureCRT or even a command prompt if telnet access is open and within minutes have an answer for them 🙂

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Remote Access/Control Apps

I must say I have used a number of remote control/access programs through the years and LogMeIn still delivers the most reliable products.

From their FREE version of remote access to their Rescue app you can’t ask for much more. You can even download their apps on most smartphones running iOS and or Android operating systems. And to me that is truly what I call remote support. When I can pull out my smartphone and remote in to a server and fix problems on the go without having to get my laptop out and pull over and try to find free Wi-Fi somewhere unless I guess you have an all-access wireless card from one of the big mobile carriers.

With that being said I use LogMeIn products daily and mostly the free version and I am not sure how I could operate without them!


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LightSpeed Web Filter Appliance

Our new LightSpeed web filter “Total Traffic Control 8” is now in place and has been very impressive so far compared to the districts old web filter appliance that I won’t mention yet.

Choosing to go in-line is way better than a standard proxy scenario where your users browsers are just pointed to a fully qualified domain name or the proxy servers IP address. New proxy workarounds seem to pop-up daily and now that we are forcing all traffic to roll through the TTC box most of that traffic is now getting blocked!

I must say that the reporting is also top-notch compared to other products on the market that are of this caliber and capable of filtering traffic of an enterprise network.

So if your business or school district is in the market for a new web filter I believe it would be worth your time to check out LightSpeed Systems web filter appliances…

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Meebo Chat Widget

Well I just added the Meebo Chat Widget for customer support and or general chats on my site with fans, customers, or my old gamer friends! Adding the code to the WordPress sidebar was pretty simple since I already had a account. Meebo is an online IRC channel that integrates multiple chat clients/social networks into an online website that also has its own downloadable client for mobile use on pretty much all smartphones. I use it mostly to combine all my instant messenger accounts into one solution including Google, Yahoo, AIM, & Windows Live. All your contacts from each individual chat client will appear inside your Meebo client list. So whether you are at home, work, or on the go and using your pc computer, MAC, iPhone and or Android phone you can simply sign on to Meebo anywhere the internet is available and all your chat clients and contacts will be accessible. Best of all this solution at this time is Free of charge! I also use Trillian instead of Meebo on occasion if I want more of a cleaner cut approach.

Anyway feel free to hit me up for tech support consultation, overall tech help, or just to say hi if you see me online.

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Monday mornings in the Tech Field

Well another weekend has slipped by and Monday morning is here upon us again. In my world that usually means putting out fires all over the place. From the network switch that bounced over the weekend to the conference meeting that nobody told me about on down to guess what? I cannot access this website and need to NOW sorta thing.

Yes Monday morning has come again and closing time can’t get here quick enough…

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Hello world!

Welcome to Craig Ellegood’s WordPress site. I will be filling this site/blog with tons of info you will need or at least find interesting about me and my life and my interests in personal and career!

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