For those of you needing quick access to a CIDR/Dotted-decimal cheat sheet, we are providing you with the one below. This schema provides you with the CIDR notation, starting with /3, its Dotted-decimal counterpart, and the total number of available subnets within each network block:
| CIDR |
Dotted-decimal |
Subnets |
| /3 |
224.0.0.0 |
536870912 |
| /4 |
240.0.0.0 |
268435456 |
| /5 |
248.0.0.0 |
134217728 |
| /6 |
252.0.0.0 |
67108864 |
| /7 |
254.0.0.0 |
33554432 |
| /8 |
255.0.0.0 |
16777216 |
| /9 |
255.128.0.0 |
8388608 |
| /10 |
255.192.0.0 |
4194304 |
| /11 |
255.224.0.0 |
2097152 |
| /12 |
255.240.0.0 |
1048576 |
| /13 |
252.248.0.0 |
524288 |
| /14 |
255.252.0.0 |
262144 |
| /15 |
255.254.0.0 |
131072 |
| /16 |
255.255.0.0 |
65536 |
| /17 |
255.255.128.0 |
32768 |
| /18 |
255.255.192.0 |
16384 |
| /19 |
255.255.224.0 |
8192 |
| /20 |
255.255.240 |
4096 |
| /21 |
255.255.248.0 |
2048 |
| /22 |
255.255.252.0 |
1024 |
| /23 |
255.255.254.0 |
512 |
| /24 |
255.255.255.0 |
256 |
| /25 |
255.255.255.128 |
128 |
| /26 |
255.255.255.192 |
64 |
| /27 |
255.255.255.224 |
32 |
| /28 |
255.255.255.240 |
16 |
| /29 |
255.255.255.248 |
8 |
| /30 |
255.255.255.252 |
4 |
| /31 |
255.255.255.254 |
2 |
| /32 |
255.255.255.255 |
1 |
Our list of the Top 10 Global Spammers is out. The biggest surprise on the list is Korea, as it takes over the number one global spammer spot from China. With the improved high speed internet infrastructure in Korea and ease of network access, we knew Korea would be on the rise. We just did not expect it to be so soon.
Here is our complete Global Spanner Top Ten List for the first quarter of 2010:
- Korea
- China
- India
- Russia
- Turkey
- Viet Nam
- Ukraine
- Brazil
- Venezuela
- Pakistan
Here are the countries in our Top Ten Global Spammers list:
Global spam problems have significantly increased during the first quarter of 2010, with a rise in snowshoe spam and an exponential growth in Botnet spam distribution.
Snowshoe spam, which rose dramatically during the final quarter of 2009, before tapering off in January, is now experiencing resurgence. Snowshoe spam is identified as a central point of spam origin, using a wide variety of IP addresses to cloak the span. These addresses are typically within a /24 range but may encompass much larger address blocks. In this type of operation the spam is spewed from a network, rapidly spanning through the IP addresses within the network, emitting spam in a wide footprint. The intent is to make the technique more efficient and more difficult to identify. Read more…
PHP 5.2+ offer an excellent function for validating IP Addresses: filter_var().
The filter_var() function offers several flags: FILTER_VALIDATE_IP, FILTER_FLAG_IPV4, FILTER_FLAG_IPV6, FILTER_FLAG_NO_PRIV_RANGE and FILTER_FLAG_NO_RES_RANGE, used to filter or validate IP addresses based on whether the address is IPv4, IPv6 or within a reserved or private network range.
Read more…
Country IP Blocks has introduced Access Control Lists by Continent to allow additional options for network managers and webmasters.
Our Continent Access Control Lists are located on our continents page.
Listed continents include Africa, Antartica, Asia, Europe, North America, Oceania and South America.
A complete list of countries by continent is available here.