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Password Recovery on a Cisco 2500 Series Router

Command Line

If you have built a home lab (or are running really ancient hardware in production), you may find yourself in need of resetting the password configured on a 2500 series router. Depending on the router platform, the syntax is different. Here's how to do it on a 2500:

1. Reboot the router and send a break sequence to enter ROMMON mode. Break sequences can be sent using a Ctrl+Break key combination, or if you are on a system that doesn't have a break sequence, try using your terminal software to send a break sequence.

2. (optional) Type the letter O and hit enter. Record the existing setting, it's most likely 0x2102.

3. To reset the configuration register and have the router bypass the startup-config, type the following:

o/r 0x2142

To boot the router, type the letter i and hit enter.

APC 9211 MasterSwitch Password Reset Procedure

I recently purchased an APC 9211 MasterSwitch PDU for my home lab. I wanted the ability to remotely power up and power down devices so I can lab while on the go and not have equipment running 24/7. This specific device was acquired from a liquidator on ebay for less than $100 USD, which compared to the newer Smart PDUs on the market is a fraction of the cost.

This device has been discontinued by APC for quite some time, however these things are rock solid and so far this unit has been performing quite well. However, there was one problem when I tried to manage it... the previous owner didn't clear the password and I was locked out.

Linux crippled by a second

If you administer Linux servers or network appliances running Linux under the hood, you may have had to deal with high CPU utilization as a result of the Leap Second that was introduced this past Saturday. In fact, as a result of this leap second and some key software not being equipped to handle it, Amazon Web Services and many other web sites took a performance hit.

If you haven't heard of a leap second before, it's simply the addition of one second to the UTC clock to realign time with solar time

Turn your Mac into a TFTP Server

If you are working on some gear and need to tftp a config off a box or upload a new version of code, you might find yourself scratching your head when it comes to setting up the TFTP server built-in to Mac OS X. I know I did. This little tutorial is meant to show you how to quickly and easily get TFTP going on a Mac (in my case, a Macbook pro running Snow Leopard (Update below for Mavericks)).

First, download TFTP Server. The developer's site has a copy. Once the dmg is open, drag the application to the applications folder to install.

Tekcert Forums - One Year and Counting

I like to recognize milestones when they come along... birthdays, anniversaries, project deadlines. So, I'm taking a few minutes to recognize that the Tekcert forums were opened up one year ago today.

In that time, we've had many users sign up and create posts, or simply respond to someone else's post. Here are some statistics for the first year:

Users: 691

Forum Threads: 215

Thread Comments: 690

Percentage of Site Traffic: 2%

Obviously, these forums are no where near as large or well traveled as other sites. That isn't really the goal I had with creating them though. If they have helped people get answers to questions, then they are serving their purpose.

Thanks to everyone who has signed up and posted questions and comments!

How to do Crtl+Break sequence in SecureCRT without a Break Key

Command Line

So, for the past couple years I've been using a Mac Book Pro for the majority of my writing, but still relied on a Windows platform for most of my command line work. I recently was faced with the need to perform a password reset on a device using Secure CRT on my Macbook Pro, and wouldn't you know it? There's no Break key! Here's how I got around this issue, if you have another way to do it, please feel free to share in the comments below.

1. Start out by establishing your console connection.

Cable Un-Management

This video has been out for a while and I'm sure many of you have seen it, but I have to share for those who haven't. Don't let this happen to your data centers...

Cisco Live 2012 Wrap Up

Well, Cisco Live 2012 in San Diego has come to an end and most people have likely returned to their homes and daily routines. Personally, I have caught up on email and am now taking on the deluge of tasks at work head on.

I've got some notes from my last session, but they need some clean up before I can post them. Also, I've got a couple pictures that I'll try to upload this week. 

All in all it was a great conference this year. I learned a lot and should have enough material for a few solid blog posts in the weeks ahead. If anyone has any links to stuff they want to share from CL 2012 San Diego, feel free to post them in the comments below. Thanks!

Frame Relay for the R&S CCIE Candidate - Session Notes

Attended the Frame Relay Session for R&S CCIE Candidates Wednesday morning. The instructor, Johnny Bass, is fast becoming one of my favorite teachers of CCIE material. His no-BS straight to the point style is great for covering CCIE material. Like yesterday’s IPv6 session, I jotted some notes and wanted to share them here.

Key points about LMI
Three types of LMI –
Gang of four, then ANSI (T1.617 Annex D, and then ITU (Q.933 Annex A)
LMI type needs to match Frame relay switch

Virtual Circuits
    Switched Virtual Circuits (SVC) – temporary, like a phone call. Setup then torn down
    Permanent Virtual Circuits (PVC) – nailed up, appears like a permananent connection

Layer 3 to layer 2 mapping

Networking Nerd

Just met Tom Hollingsworth randomly in the hallway. Here's a shout out to "the" networking nerd. Check out his blog:

IPv6 for the CCIE R&S Candidate - Session Notes

Today I attended the IPv6 for CCIE R&S session presented by Johnny Bass, CCIE #6458 and Cisco 360 master instructor. Totally awesome presentation! I jotted some notes and figured I’d post them here to share.

All the content in the session (BRKCCIE-9592) is regarding the R&S 4.0 version blueprint. “If it’s not in the blueprint, it’s not in this session”

Different Addressing Types

  • 2000::/3 – Global Unicast
  • FC00::/7 – Unique Local Unicast
  • FE80::/10 – Link Local Unicast
  • FF00::/8 – Multicast

Prefix Subnet Interface/Node ID
32 to 56 bits 32 to 8 bits 64 bits

Note: The interface ID can be either EUI-64, use Privacy Extensions (RFC 3041), or locally configured.

Cisco Live 2012 - First Day Review

The first full day at Cisco Live 2012 was a blast! I picked up quite a bit of info on MPLS (stay tuned for a future blog about that). Also, I met Terry Slattery who is a tremendously nice guy and for those who don't know, is a distinguished CCIE

The World of Solutions is great, lots of great vendors and booths. Tons of free t-shirts and trinkets. And of course the free food and beverages are nice too. The WoS is always well done and this year is spot on.

The wireless systems at CLUS have been plagued up to this point. They were working hard on it though and have said they've rectified the issues. We'll see how the rest of the week goes, hopefully a little smoother. Down? down? I'm guessing everyone is trying to download their PDFs since we didn't get them on a USB flash drive this year...

The iPhone app isn't loading either. I tried to save some paper by just using the iPhone app. Hope it's up tomorrow, I'd like to get to my schedule so I know which sessions to go to. 

Update: Looks like they fixed the issue over night. Just in case it happens again, I've emailed myself the schedule.

Cisco Live 2012

Cisco Live 2012 Logo

I have arrived! Here's what I've got so far:

Registration is a breeze.

There are Cisco people everywhere directing traffic, even in the hotel lobby.

The bus is a little slow, but beats walking uphill.

Weather is perfect! Why don't I live here yet?

Keep checking back, more to come...

BGP AS List and potaroo

Have you ever wanted to see a list of all the BGP Autonomous Systems Numbers and what organization they are associated with? I did this morning and after some searching, here's what I found.

There is a cool website (cool in a nerdy BGP statistics sort of way) called that is "the personal site of Geoff Huston." The site has a blog and provides links to a variety of statistical analyses and reports on Internet BGP data.  No surprise that Geoff appears to work at APNIC.

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