Internet Packet filtering firewalls: These firewalls are usually a part of the network router. Each packet passing through this firewall is screened and compared to an administrator-defined set of criteria. Depending upon the criteria, the packet is either forwarded to its destination or dropped from the network. These firewalls don’t cost much, and don’t slow down network performance. Network Address Translation (NAT) firewalls: NAT routers do all that packet filtering firewalls do. In addition, they hide the IP addresses of computers on the network. Circuit level gateways: These firewalls do not filter individual packets. Rather, they monitor TCP handshaking between packets. What’s more, each packet that passes through a circuit level gateway appears to have originated from the gateway and not the computers behind it. Thus, network computers stay protected. These gateways are relatively low-cost. Business - List of business/finance/loan/mortgage resources more 1 2 3 4 5 Computers - List of computer hardware/software/peripheral resources more 1 2 3 4 5 Internet - List of webhosting/webdesign/internet marketing resources more 1 2 3 4 5 Software - List of software resources more 1 2 3 4 5 Web Design - List of web design/development resources more 1 2 3 4 5 Web Hosting - List of web hosting resources more 1 2 3 4 5 Web Promotion - List of search engine optimization/internet marketing resources more 1 2 3 4 5 Web Resources - List of other web resources more 1 2 3 4 5 Recreation - List of travel/hotel/cruise resources more 1 2 3 4 5 Casino - List of online gambling/poker/blackjack/roulette resources more 1 2 3 4 5 Health - List of online pharmacy/hospital/health resources more 1 2 3 4 5 Shopping - List of online shopping/gift resources more 1 2 3 4 5 Miscellaneous - List of all other resources not stated above more 1 2 3 4 5   Application level gateways: These gateways are also called proxy servers or proxies. They are actually application-specific circuit-level gateways. These gateways don’t allow any ftp, gopher and telnet traffic through. Proxies are configured to only let through http:post, get and other specific commands through. Application level gateways can also monitor user log-ins and log-outs, as well as user activity. They are very secure, but significantly slow down network performance. Stateful multilayer inspection firewall: These firewalls combine the other four types of firewalls. They screen packets, determine their legitimacy and evaluate contents of packets at the application level. They are highly secure, very expensive and need to be administered by highly competent network personnel. Basic Recognition of a JavaScript To get started with JavaScript, you will want to be able to see the tag that will set a script apart from the HTML. The tags used to begin and... onMouseover: Your first Script Well, its time to try out your first javascript. This one is nice because we don't have to deal with adding the script tag. Using Buttons for JavaScripts To write scripts using buttons, we will first need to know how to place a button on the page. To do this, you will need to use the.Windows Vista.