Ethernet Networking- P6:One of the biggest problems when discussing networking is knowing where to start. The subject of computer networks is one of those areas for which you have to "know everything to do anything." Usually, the easiest way to ease into the topic is to begin with some basic networking terminology and then look at exactly what it means when we use the word Ethernet. | 138 Routing Note If you supply a firewall as a standalone appliance you may want to turn the router s firewall off. More in Chapter 10. By default most of today s small routers block packets from well-known ports. If you want to let them through or want to let through traffic from specific Web applications such as games then you will need to open the ports manually as in Figure 6-10. You enter the ports you want to open in the Start and End boxes. These make it easier to enter a range of ports. If you have a Web server or FTP server with static IP addresss you will need to open their ports for example. Figure 6-10 Configuring a router to open specific ports Finally you can usually configure Internet access policies Figure 6-11 providing access controls for specific machines on your internal network. Adding Routers to an Ethernet 139 First you create a list of workstations to be affected by the policy as in Figure 6-12. Then you indicate when you want to deny or allow access. Notice also at the bottom of the access policy screen that you can block Web sites by URL or keyword. It may not be as flexible as many standalone parental control applications but it s a start Figure 6-11 Configuring Internet access policies Note You may have noticed that this router also has a screen for configuring wireless connections. We ll look at that in Chapter 7. 140 Routing AHA Um of PCi - T List Of PCs Enter MAC Address d the PCs in this format xxxxxxxxxxxx MAC 01 OOiOOiOOiOOiOOiOO MAC 05 OOiOOiOOiOOiOOiOO MAC 02 OOiOOiOOiOOiOOiOO MAC 06 OOiOOiOOiOOiOOiOO MAC 03 OOiOOiOOiOOiOOiOO MAC 07 OOiOOiOOiOOiOOiOO MAC 04 OOiOOiOOiOOiOOiOO MAC 08 OOiOOiOOiOOiOOiOO Enter the IP Address of the PCs IP 01 i 2ieei. IP 04 1 2 MV 0 IP 02 tee teai. ip 05 0 IP 03 1B21M1 IP 06 tea imi. Enter the IP Range of the PCs IP Range 01 i ieei 0 - 1 IP Range 02 ie i t t 1 T Cancet Chenfss Figure 6-12 Setting up a list of PCs for an Internet access .
