tailieunhanh - Linux smart homes for dummies - part 3

Đây là một ý nghĩa thực tiễn rất lớn về việc ứng dụng Linux trong các hệ thống điều khiển của nhiều lĩnh vực như: quân sự, ngân hàng, và các hệ thống điều khiển nhúng, . | Chapter 3 Going Wireless 47 proper shutdown procedures before installing your card. I also recommend that you unplug the power cable. Some computers appear to be off but are actually still on. At this time you might want to install the WAP hardware and any of your wired network connections. In Chapter 4 I explain how to set up a WAP with a WRT54GL and OpenWRT software . Prerequisite information IP network address and mask The IP network address is the easiest bit of information to get most people use one of the reserved private network addresses Google RFC1918 for further details . I recommend using the mask . This allows you to have up to 254 devices on your network. The IP addresses through are for host use while and are reserved for special use. I chose this network because a lot of new equipment comes configured by default with this network address. 1 Service Set Identifier SSID The SSID is an ID that is used by networks to advertise the presence of a WAP. There is some debate as to whether it s a good idea or bad idea to permit the SSID to be advertised. Pretty much it boils down to this If you don t advertise it the script kiddies amateurs won t see it but that won t stop a more professional attacker. I use the advertisement because it makes it easier to get my friends machines working and it makes the diagnosis a little easier. Wireless channel number You must select a wireless channel number. In the United States by default most wireless devices use channel 6. In my neighborhood eight WAPs are within reach of my home. This usually means that within about 150 feet of my wireless device there is a WAP that is advertising its SSID. That also means that at least seven other users are using the same channel at the same time. It s like having a conversation with 14 people not everyone can talk at the same time. By selecting another channel you might be able to limit the .