Subnet Mask Information
Have you taken a TCP/IP class? Yes, I did a long time ago. Learning TCP/IP and the OSI Model has been the eye-opener for me that really took my consulting career to the next level. I spent a week in class and learned all the binary math to figure out which subnet mask to use that would be most efficient for a network. This was great knowledge and I am good at math, but who wants to write all that math down?
That’s why we have calculators and cheat sheets!
Sometimes I just need to know quickly what a /18 is. I mean, I know most of the standard network codes by heart, but when working on a big project it helps to know all of them. Here is a quick Subnet Mask Cheat Sheet so I don’t have to go to some other website anymore.
Subnet Mask Cheat Sheet
|
Subnet Mask |
Hosts |
| /30 |
255.255.255.252 |
4 |
| /29 |
255.255.255.248 |
8 |
| /28 |
255.255.255.240 |
16 |
| /27 |
255.255.255.252 |
32 |
| /26 |
255.255.255.248 |
64 |
| /25 |
255.255.255.128 |
128 |
| /24 |
255.255.255.0 |
256 |
| /23 |
255.255.254.0 |
512 |
| /22 |
255.255.252.0 |
1024 |
| /21 |
255.255.248.0 |
2048 |
| /20 |
255.255.240.0 |
4096 |
| /19 |
255.255.224.0 |
8192 |
| /18 |
255.255.192.0 |
16384 |
| /17 |
255.255.128.0 |
32768 |
| /16 |
255.255.0.0 |
65536 |
Click the link below for more information on IP Subnet Mask Numbers
IP Subnet Mask Numbers
Subnet Mask Calculator
I use an Online Subnet Mask Calculator when I want a quick list of the networks included within a subnet. Check it out below;
Subnet Mask Info
Site Speed is now Important
I have always thought that my site speed was important, but that was only for my users experience. But now, we as web developers need to make sure our sites don’t get too slow. First thing this means is;
Make sure you have a good web host!
If you are using a shared host for your website, you could have issues. Try to make sure your web host allows you control of your .htaccess file allowing you to speed up your site with caching. There are some hosts that do not provide that option, so check it out.
If you are using WordPress or any other content management system then you will most likely be using plugins. This can be a problem when you are trying to speed up your site since multiple DNS requests ( grabbing files from all the different plugins websites ) can be a major issue. For this reason I suggest checking out each plugin before you use it and see if you can use your own CSS/Javascript code.
SEO Tools for Site Speed
From the Official Google Blog
- Page Speed, an open source Firefox/Firebug add-on that evaluates the performance of web pages and gives suggestions for improvement.
- YSlow, a free tool from Yahoo! that suggests ways to improve website speed.
- WebPagetest shows a waterfall view of your pages’ load performance plus an optimization checklist.
Photo Source: Thanks Danny Sullivan
