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How to enable IPv6 support on a Cisco 3560 switch

If you have tried configuring IPv6 on a Cisco 3560 switch, you may have noticed the ipv6 commands aren't available by default. This often catches me when I am working on a new switch that has never had IPv6 enabled. I just had this happen tonight, so I figured I'd write a brief how-to with some background info thrown in.

Where are the IPv6 commands hiding?

Cisco 3560 switches have a feature called Switch Database Management (SDM) templates. There are various templates that can modify the allocation of system resources to better support different features. What does this mean? By default, a small catalyst switch is built to support 8 routed interfaces and 1024 VLANs. It's not generally used to route OSPFv3 and BGP (though, it can do that). So as a result, the system resources are evenly distributed among the various functions to accommodate a common set of tasks.

Cisco 4500 Series Sup7e Install Notes

One of my projects at work is to replace a couple switches with newer (and larger) 4507R+E with Sup7e. I love projects like this because they're relatively straight forward, but mainly because they are fun! Who doesn't like unboxing a $60,000USD switch and firing it up? It's like a Cisco birthday or something.

Anyway, while configuring this thing, I've noticed a few quirks... idiosyncrasies? "Features"? Whatever you call them, they're new to me and I felt like blogging about it.

SD Memory in a Supervisor

First, just an observation: Cisco now has Secure Digital (SD) memory in a Supervisor. You might be thinking "yeah, I read about that when the Sup7e came out..." However for those who were in the dark, now you know. Here's a picture to share: 

Upgrading 3750X can take longer than you think

I recently upgraded a Cisco 3750X stack to a newer version of IOS. Since the production system I was planning to upgrade had some critical systems on it, I tested the process on a stack in the lab first.

At the outset I figured "no problem, this will take a few minutes to reboot and we'll be back up and running." Little did I know I was in for a long wait... Unbeknownst to me the version of code I was upgrading to included a Microcode update which adds a considerable amount of time to the process... emphasis on considerable.

The stack was running 12.2-53.SE2 and I was upgrading it to 12.2-58.SE2, which at the time of the upgrade was the recommended 12 version (I've had problems with IOS 15 on this platform, so I'll be sticking with version 12 for now).

Cisco SG100-16 Unmanaged Switch

Need more Gigabit Ethernet? Don't need it to be a managed switch? This 16 port 10/100/1000 Cisco switch might be a quick and easy solution for you.


The Cisco SR2016T 16-Port Rackmount 10/100/1000 Gigabit Switch (A.K.A. SG100-16) is currently listing for below $200 USD and has several appealing features:

Cheap GigabitEthernet

Looking for inexpensive connectivity for your house or small business network? I was too until this past weekend when I picked up one of these:


Pretty simple little switch, you just plug it in and there's no config. I just needed some Gig-E ports and didn't want to buy a D-link, it felt wrong for some reason.

Cisco 3750 switches get some needed attention

If you have ever setup a stack of Cisco 3750 switches and thought the StackWise feature could use some improvement, well Cisco read your mind. At least that is what I thought when I first laid eyes on the 3750-X switches. Finally, dual power supplies that are hot swappable and a cool feature called StackPower that saves the day when both power supplies fail!

For those of you who haven't heard of StackWise, it is basically a feature that Cisco has offered with some of their access-layer ethernet switches and blade server switches which allows several switches connected together with special cables to be managed as if they are a single switch. This means a server connected to a port on switch 1 can talk to a server on switch 2 without ever leaving the switch stack. Plus there is an added bonus of one IP address and system to manage instead of however many switches are in your stack.

Defend the city!

The Cisco SLM2008 switch Jeremy talked about is cool and all, but does it help you defend the city?
Introducing the  Cisco SG 300-10 10-Port Gigabit Managed Switch. According to Amazon's description, not only does it aid in defending the city, it also will help you "find and defeat new Doom Syndicate enemies, including Megamind's re-programmed Brainbots!" 

Cisco Nexus Switches, with built-in Wireshark

Most of us out there have a copy of Wireshark on our PCs and laptops for troubleshooting problems as well as for learning and figuring out how protocols work. Well, what if you are troubleshooting a problem and you don't happen to have Wireshark installed? 

No problems if you are working on the Nexus 7000, wireshark is built in. Now, don't get too excited, it isn't like there is a built-in GUI (yet?). Cisco simply based their Cisco NX-OS Ethanalyzer on the command-line version of wireshark, also known as T-shark. The syntax is very similar to tcpdump in linux, here is an example:

Completely Clearing a Cisco Switch...The Easy Way!

Clearing out a Cisco switch configuration is always a
pain because VLANs are kept in a seperate file from the startup-config
(NVRAM). There's two ways to clear a switch back to the factory defaults
- the easy way and the REALLY easy way:

The easy way

Switch# write erase
Switch# delete flash:vlan.dat
Switch# reload

The REALLY easy way -

Hold the "mode" button on the front of the switch for 10 seconds. The
lights will blink then go solid - the switch completely wipes all
configuration and then reboots. Obviously, this method only works on
stackable switches as the chassis based switches do not have mode

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