!NSFW

I just downloaded the wordpress blogging app from the apple app store. This is going to be a test post to a see how useable this app is.

The app seemed to crash once while I was writing this post. But since it saved a draft locally, I was able to get back all my content within seconds.

Generally GBICs have been open so you can use any brand. Cisco equipment won’t accept “just any vendor’s” compatible SFPs. I found this out the hard way last year trying to save some money when I purchased a couple of OEM SFP transceivers from Dell to use in a Cisco switch. Plugging in the SFP module would disable the port. The switch’s firmware supposedly checks the identifying data in the SFP’s internal Flash memory, and if it isn’t built by Cisco, the switch refuses to enable that slot. It’s not only Cisco that does this. Other vendors like Extreme Networks and 3Com are also reported to do the same.

I had to to give in and purchase a $300+ Cisco branded SFP from CDW to use with this switch. Fortunately, there is a way to disable this check in the switch depending on the IOS version installed on the switch.

Issuing the following commands will allow for unsupported SFPs and wont disable the port.

switch(config)#service unsupported-transciever
switch(config)#no errdisable detect cause gbic-invalid


You will be presented with a warning after the first command with something to the effect that if you experience any problems with the switch, Cisco may deny support if the cause is determined to be the ‘unsupported’ SFP.

There are a number of ways of doing this. The most commonly and easiest to use are meta refreshes and javascript redirects. a better method would be to use a server-side redirect (PHP, ASP, .Net). I will list examples of each and also some of the disadvantages each have.

Meta Refresh
Using this meta tag in your html page will Redirect the page after a given interval to to the address specified.

This code will redirect the page to ibnmasud.com after 5 seconds:
<meta http-equiv="refresh" content="5;url=http://ibnmasud.com" />
Setting the interval to 0 will redirect to ibnmasud.com immediately:
<meta http-equiv="refresh" content="0;url=http://ibnmasud.com" />
Disadvantages:

• Using the back button will take you back to the redirect page which will then redirect you again. Firefox, Opera, and Safari ignore this behavior and IE users can double-click the back button. Also referred to as “brokeback buttons”.
• Can easily be disabled on the client side. If disabled, the page will not redirect.

Javascript
Javascript gives you a lot more flexibility in redirecting pages.

Location.href Method
Including this script on a page will immediately redirect visitors to the URL entered. This method creates two items in the browsers history. One for the page including this script and one for the page that this page will redirect to.
<script type="text/javascript">
window.location.href="http://nsfw.ibnmasud.com/";
</script>
So it works the same way as a meta refresh in that it can lead you into a loop if you press the back button.

Location.replace Method
The Location.replace method solves the loop problem by replacing the content of the browsers history with the redirected page’s address, i.e, only one item is created in the browsers history.
<script type="text/javascript">
location.replace(\'http://www.example.com/');
</script>
Disadvantages:

• Google will not index pages redirected using javascript.
• Can easily be disabled on the client side. If disabled, the page will not redirect.

PHP
A basic permanent (301) redirect in PHP uses the code below:
<?PHP
// This header tells the client the HTTP status code of the page
header("HTTP/1.1 301 Moved Permanently");
// The client must then be informed where the URI is now located
header("Location: http://www.example.com/example");
?>


Using .htaccess for Redirection

When using the Apache web server, directory-specific .htaccess files (as well as apache’s main configuration files) can be used. For example, to redirect a single page:

Redirect 301 /oldpage.html http://www.example.com/newpage.html

To change domain names:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^.*oldwebsite\.com$ [NC]
RewriteRule ^(.*)$ http://www.preferredwebsite.net/$1 [R=301,L]

Disadvantages:
Use of .htaccess for this purpose usually does not require administrative permissions, though it can be disabled.