Tweet forwarded by @russruns

cmross: Will seek this out later today.  Steve Jobs banner in the Windy City a nice tribute http://t.co/UjlQ2eG0 via @zite

Original Tweet: http://twitter.com/cmross/status/123434197460324352

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Steve Jobs -- 1955-2011

 

 

http://www.apple.com

http://www.apple.com/stevejobs/

F5 LTM GTM IPv6 quick hit

Just quick note, F5 products LTM and GTM work just great with IPv6.  But IPv6 address shortening (double-colons '::') is not permitted in the GUI or tmsh.

LTM and GTM are Linux based systems, so if you are using BASH, the standard rules apply.

But if you are using the GUI or tmsh, IPv6 addresses must be fully completed.

This:

fe80:0:0:0:201:d7ff:fed4:d041

Not this:

fe80::201:d7ff:fed4:d041
    ^^  Cannot have a double colon.

IPv6 SLAAC(er)

Promoted as a feature of IPv6, allows a device to connect to a network and receive an addresses without the administrative overhead of managing a DHCP.

But there are a few limitations that limit its usefulness in an enterprise environment:

• SLAAC only works with /64 subnets. No more, no less.
• SLAAC does not hand out DNS information (or any Windows domain specific info).

You get an address, a fixed subnet, and a default gateway. Period. This doesn't make it entirely useless, but definitely SLAAC is not a DHCP killer.

To enable a Cisco router to being making SLAAC announcements, all you need to do is configure an interface with an IPv6 address and a /64 subnet:

interface GigabitEthernet0/2
no ip address
duplex auto
speed auto
ipv6 address 2001:1890:1208:240::1/64

This line:

ipv6 address 2001:1890:1208:240::1/64

causes the router to begin making ND announcements which permit other devices to SLAAC themselves. We can verify announcements with a show ipv6 interface:

V6-R1-2911#sh ipv6 int gi0/1
GigabitEthernet0/1 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::xxxx:xxxx:xxxx:xxxx
No Virtual link-local address(es):
Global unicast address(es):
   2001:xxxx:xxxx:xxxx::1, subnet is 2001:xxxx:xxxx:xxxx::/58
Joined group address(es):
   FF02::1
   FF02::2
   FF02::1:FF00:1
   FF02::1:FFFD:CCC1
MTU is 1500 bytes
ICMP error messages limited to one every 100 milliseconds
ICMP redirects are enabled
ICMP unreachables are sent
ND DAD is enabled, number of DAD attempts: 1
ND reachable time is 30000 milliseconds (using 30000)
ND advertised reachable time is 0 (unspecified)
ND advertised retransmit interval is 0 (unspecified)
ND router advertisements are sent every 200 seconds
ND router advertisements live for 1800 seconds
ND advertised default router preference is Medium
Hosts use stateless autoconfig for addresses.
V6-R1-2911#

So you've got IPv6...

...now what?

This site contains a list of websites with verified IPv6 connectivity. Regularly updated and tested. Also provides the resolved IPv6 address so you can perform basic ping testing in case your DNS is flaky (anyone else have this problem?).

Global IPv6 Deployment Progress Report

Haven't ruled out a problem on the local end, but we do get better (but not 100%) responses from:

Public DNS servers:

	IPv6	IPv4
Open DNS	2620:0:ccc::2 2620:0:ccd::2	208.67.222.222 208.67.220.220
Google Public DNS	2001:4860:4860::8888 2001:4860:4860::8844	8.8.8.8 8.8.4.4

Flickr API

This falls into the category of both work and fun.  Many of my clients use an online host to manage their photos. My personal favorite is Flickr. Whether you’re a professional photographer looking to expand your market or show off your latest, or you’re in a sales/marketing/promotion role and sharing pictures from the latest trade show, or simply have a need to share more than a handful of digital photographs, a photo-specific hosting site makes the job much easier and allows you to focus on results rather than the process.

Flickr provides the ability to easily embed photos in other applications and a highly extensible API for extracting and using photos for your own customized needs.

Before you begin creating scripts, you’ll need a Flickr API key.

From your account page, click on the “Sharing & Extending” tab.

Scroll down to “Your API keys” and click on the link to the right, which likely says “You have no API keys assigned to this account.”

Click on the “GET A KEY” button.

For now, we’ll stick with non-commercial applications, so click on “APPLY FOR A NON-COMMERCIAL KEY”.

You’ll need a name and description for you app.  For now, we can name it “Test Key” and give it a similar description. After reading the terms of use, confirm and check the boxes and click “SUBMIT”.

You’ll be given two hex strings, a “key” and a “secret”.  Since we created non-commercial keys, save these and don’t share with anyone.  You’ll want to copy/paste someplace for quick reference, but you can always retrieve them from your account page if necessary.

With your API key, we can now begin writing a script.

Once again, Perl provides a readily available repository called Flickr::API.  Use cpan to install:

cpan> install Flickr::API

I’d also recommend having Data::Dumper available.

cpan> install Data::Dumper

The first script will simply confirm your perl module is working properly and your API key is functionally.  Fortunately Flickr provides a test method.  Make sure to replace your_key_here with your Flickr API key (not your secret).

# C:\Perl\bin\perl.exe

use Flickr::API;
use Data::Dumper;

my $api = new Flickr::API({'key' => 'your_key_here’});

my $response = $api->execute_method('flickr.test.echo');

print "Success:\t$response->{success}\n";
print "Error code:\t$response->{error_code}\n";
print "\n\n\n";
#print Dumper ($response);

For now, leave the last line (Dumper) commented out. Running the perl command should give you these results:

R> perl Flickr-test.pl
Success:        1
Error code:     0

If the results are flipped (success: 0 and error: 1), there’s a high probability your key isn’t correct, or there were problems with the Flickr::API module.

Standards

We are regularly called on to report on the latency and packet loss to a remote location.  We allow the perl script to schlep the data into a csv file, which then gets exported into Excel to produce a graph.   Excel has great capability to create charts on-the-fly, edit, and annotate. But consider these two graphs, charting exactly the same data set:

 

 

The graph on the bottom produces a much dramatic display of latency, and washed out the packet loss.  The top graph emphasis the packet loss, while reducing the impact of the latency.  Both are accurate, but the tell a different story.

Typically, charts aren’t viewed in a vacuum, but are rather compared against other charts—charts of other locations, or historical charts.  For this reason, it’s important we compare charts of similar scale.

Not only must the axis be the same, but the proportions of the X and Y axis should be similar.

As part of the post-mortem templates, or performance report template, include graph standards: latency maximums, time-scales, and graph sizes.  It will make it easier for everyone to compare events as needed.