Misc

As you all probably noticed, the rate of newly published articles has slowed down for a couple of month now and probably will stay that way in the close future. This is manly due to more work, more business trips and a lack of mood during my spare time. Even though I did not lose interest in writing but well, you know, mankind is lazy

Nonetheless there are a two minor changes/upgrades within the blog you mind find useful/interessting.

First of all I just found a CCIE Study Wiki with tons of links to the different topics of the R&S Blueprint. The guy who maintains the wiki also wrote some articles to the different topics. Even though this Wiki is aimed for CCIE candidates it might be an interesting read for all people in search of knowledge about networks. Its the only page I know so far which has direct links to other blogs in such an organisation, it claims there are about 3000 links at the moment. Either click on the CCIE Study Wiki link at the right side or here to get to the Wiki.

The other little upgrade is a rating option for each article on the blog. WordPress added this option some when and well I just didnt notice until I saw it on another WordPress blog It would be very helpful for me if you could rate the articles so I know where I have to do some improvements or even rewrites

1st Anniversary

Today is Just another CCIE’s first anniversary. Kinda strange since this means I got my number since a bit more than one year (already got CISCO’s 12 Month reminder) and I should start preparing for my recertification. But it does not feel like one year, more like maybe 6month or so

Also nice to see the blog got over 30′000 hits lately, even though Im really really lazy with writing updates (still working on the solution guide for the lab..) since a few month but during busines days the blog gets between 90 and 110 hits a day which is still good. Might be better if there would be more articles and more updates around.

Dunno this is somehow a nonsense article but I thought its worth to mention.

Anyway thanks to all readers and commenters and enjoy your day

best regards

Michel

IOS Version 12.4(22)T and Banners

Its quite some time since the last article but work keeps me busy and at the moment I work in Singapore which means even less spare time to spend with blogging or other techie stuff. But nevertheless I thought I share the following thingy.

Usually Im used to configure  motd and exec banners with a layout similar to this:

#########################################################################################
#                                                                                       #
#                          UNAUTHORIZED ACCESS PROHIBITED                               #
#                                                                                       #
#       We will kick your but if you try to hack this device                            #
#                                                                                       #
#          or other bla bla bla                                                         #
#                                                                                       #
#########################################################################################

Nothing special and like everything a question of your taste, but the fun part is, is that the IOS 12.4(22)T will not accept this banner. Well not accept is the wrong word, it does accept it, but it will not save nor display it. It just eats the input and says nothing. If you have a look into the running config, thats all you see:

banner exec ^CC
banner motd ^C

The banners just disapeared. So whats it all about? 12.4(22)T does not accept a line which starts with the # symbol, its simply that, if you add a banner with the # at its beginning, it will just accept but not write it. There may be other signs which are not accepted, but I know that * works So do not wonder about why you dont see your banners, you either have a # at the beginning or you just found another symbol which is not compatible with Cisco

Networkers Review

I finally got some time to write a little review over the past week in Barcelona.
So far I can say that it was a great experience, just the sheer knowledge is overwhelming. If I had the time for it I could spend at least 3 weeks with working and reading the slides we got. But lets start somewhere else.

I arrived in Barcelona on Sunday afternoon and got to the hotel (Hesperia del mar ****) by taxi. After the check-in I went to the room and was a bit surprised, the room layout was a bit strange. A quite small room with a big beed and (in comparison to the room) a real big bathroom. Well nothing bad about this but usually its a bit different Afterwards I just got out of the hotel to check the closer neighbourhood to get to know where I can find what, sadly there was no store close to buy some water (which is something I usually do).  So I went back to the hotel did some surfing (Internet Access is free, but not very stable and there sadly was no open AP close by) and reading until Cisco opened the gates for the registration. I thought I gonna get there early cause I didnt know how long it would take, to my big surprise I went in and got my stuff after about 3minutes. It was just like entering your name into a notebook, getting your batch and then the Networkers bag, with presents and informations about the conference. After that I went to a shoping mall close by where I thought I might be able to buy water but guess what, its sunday (stupid me) and the market store was closed, no other open store was selling water in bottles. End of the story I had to use the bottles in the room bar which is in my opinion just too expensive but well…
I went back to the hotel thinking I could spend an easy evening/night in the hotel and its restaurant without having to go out and look for a suiting restaurant, another gotcha the reception told me, that their restaurant is closed over the weekend.. thanks! I ended up in a close by local restaurant which was serving good food.

Going over the Networkers itself I got a few impressions and gotchas I probably file under lessons learned:

• It was the first, only and last Techtorial I ever took. For myself I cant stand it to have 8h talk and listening for US $500 (I think it was). Even though the topics were good and the slides also (happily I got a CD with all slides hehe) but I tend to forget stuff I heard quite soon if I do not do anything with it (write it down, test it, make a testlab, you name it) and I cant just sit there and listen for 8h. But thats just me.
• The food is well.. Im no gourmet but I like good food so the next time I gonna frequent the restaurants close by more often
• Either take a hotel which is closer to the conference or get better walking shoes. My feets were hating me after that week since I did not get some proper shoes with me to walk the distance from the hotel to the conference and back 2-4 times a day.

The Sessions (except the Techtorial that is ) where great, I luckily had (I was told other stories) native English speakers on all sessions I attended which really helped a lot to get what they were talking about. I got out of every session thinking about that stuff and trying to match it on our companies environment, comparing the actual situation and finding the points where we can make some reasonable improvements. I think that shows that the sessions were good. And the good thing is we got all slides from all sessions, which means I can have a look into every session I was not able to participate due to lack of time or schedule problems with other sessions.

The Lab Session itself was neat, I really wish Cisco allowed us to schedule more than only one session per networkers. But well the world isnt perfect so..

A special thing to mention is the round table I was invited to. I really enjoyed (besides the free EUR 40 Gift card, which allowed me to buy a book about ASA’s for EUR 6 , did I mention already that I bought myself an ASA 5505? ) the discussion with Mary from Cisco and the other guys, the first time I felt somehow that Cisco is actually asking their customers and partners on what they think about stuff the plan to do. Sadly we’re not allowed to talk about what Cisco is planning or better thinking about. Mary also mentioned that there are options to participate in more things like this. Im still thinking about if I send her a mail or not

Another highlight was that I met Stretch (packetlife.net) in person, I’d really like to send him some congratulations on his passed CCIE written exam at this point. Well done and it was nice meeting you in person. Through Strech I also met Greg Ferro (Etherealmind) and Kevin Dorrell (dorreke.wordpress.com), sadly we only had just a short time to talk together but I guess we’ll meet again, somewhen and somewhere and hopefully with a lot more time

Cisco Networkers 2009 in Barcelona

Im going to attend the Cisco Networkers for the first time now and I am really looking forward to its start tomorrow. Besides of having (finally!) time to get into learning new things the weather here is just great, compared to home. As I went out of my flat this morning it had about 3-4 Degrees Celsius and here we have  more like 15 and blue sky!

Well and thats my schedule for the coming week:

Monday January 26

09.00 AM – 6.00 PM: IPv6 Technology Update

Tuesday January 27

10.15 AM – 12:15 PM: Multilayer Campus Architectures and Design Principles
01.00 PM – 02.30 PM: Round Table about recertification
04.15 PM – 06.15 PM: Advanced Cisco Catalyst Virtual Switching Systems (VSS)

Wednesday January 28

08.30 AM – 10.30 AM: Deploying Wired 802.1x
01.30 PM – 03.00 PM: Migration Considerations when buying MPLS VPNs from Sevice Providers
03.30 PM – 05.30 PM: Understanding and Preventing Layer 2 Attacks

Thursday January 29

08.30 AM – 12.30 PM: Designing and Implementing Manageability using Cisco IOS Embedded Event Manager (EEM)
01.30 PM – 03.30 PM: QoS Decomposed

Testing Connectivity

Testing the connectivity is something that basically came up for me with the CCIE labs to verify the end-to-end connectivity in the Lab. But the more and the bigger networks I implement the more its a thing I like to do before I really install them (actually I configure them 99% of the time in our lab). In the end it will not verify that everything works correct but it gives me a good level of confidence before installing the devices on site.

Which thing to use to test heavily depends on the platform and the IOS version. There are two options to test I know of:

• TCL Scripts
• Switch Macros

Switch macros are for switches and TCL Scripts should nowadays work on every router with a kinda up to date IOS Image (for more informations on which IOS and feature set to use klick here). I personally prefer the TCL Scripts over the switch macros and am quite happy that the Cat3k switches with an IOS version of 12.2(40)SE and above are now TCL enabled too. But to have the article complete I’ll show on how to do the ping tests with switch macros too.

Cisco’s Traceroute Implementation

Given this topic is very basic and small but its allways good to have those informations handy, you never know when you need it

Cisco’s Traceroute implementation uses a mix of UDP and ICMP packets. A Cisco devices sends 3 UDP packets (default) with an invalid port address and a TTL of 1. Since the TTL is set to one the first router in the path will send a time to live exceeded in transit message (ICMP Type 11, Code 0) back to the source, since its not the target of the packet but it cannot forward the packet to the next hope due to the TTL of 1.
After the device received the 3 ICMP packets it will send 3 UDP packets again but this time with a TTL of 2. The same process recurs until the destination is reached. The destination then will send destination unreachable (port unreachable) messages (ICMP type 3, code 3) instead of the time to live exceeded messages. The traceroute process then knows that it reached the destination and the process can be stopped.
The device can build the path to the destination based on the ICMP messages, since those messages use the interface towards the source device as their source address.

Lab Challenges

Hi all
Based on the “very popular” (15 participants) Lab Challenge poll I gonna create an all in one (except IS-IS ) routing challenge and also a switching lab. Maybe later on an OSPF and a RIPv2. But first Im working on posting the solutions to the other two labs here. The solution for the EIGRP lab should be up in the next few days.

Best regards

Michel

Vote for the Lab Challenge

Some time ago wordpress added a feature to create polls inside the articles. I thought it might be time to test it since the last time I asked for input I got no response, looks like people are to lazy to write something and just voting in a poll looks to be a lot less work
So let me know which kind of topic you’d like to see as next Lab Challenge.

IOS Featureset change whithin a 3750 stack

Im currently working my way around the 3750 stack implementation, even though this technology has been around for years, I just got my hands on it a week ago. After reading the Cisco configuration guide about Managing Switch Stacks I’ve finished with still some questions left. One of these was about the whole IOS management of the stack.

It is written in the guide, that the Switch Stack itself will automatically do IOS up- or downgrades itself (auto-upgrade) as long as the switch in question is at least partial compatible to the stack and the IOS feature set on the Stack and the new switch are the same. But what to do with new stack members that do have a different IOS feature set? In my example an IP Services and an Advanced IP Services feature set and I want to have the Advanced with crypto set on both switches. Since Im too lazy to take out the new switch of the stack I thought there has to be an option to do that over console access and well here we go.