Don't know anything about Comcast, but they definitely need to know if there is a router in line. This is because at the most basic level, there are two points of failure: communication between the PC(s) and router, and communication between the router and the modem. Example: When I had Verison DSL, they leased (or assigned) addresses for only 8 hours. When I would loose communication to the Internet it was usually because the WAN IP was released, but then the renewal failed. (this was a horrible system and I dropped their service in frustration). The resolution was rebooting both the router and DSL modem, sometimes multiple times until the router picked up an IP address. Usually no action was required with the PC. Since changing to RoadRunner cable, these DHCP problems have completely disappeared. On rare occasion I will loose communication to the Internet. I use a wireless link to my workstation. The microwave oven (on rare occasion) interferes and will cause communication to drop. Even though I use static IPs on the LAN side, I still occasionally have to disable and re-enable the network adaptor card on the PC to resolve a dropped communication problem between the PC and the wireless router. The above outlines two different points of failure with the same end result: communication failure with the internet. The problems are completely different and therefore the solutions are unrelated (I used the microwave example because not only is it real; it should give an idea of the wide range of variables that can create trouble). This is why a tech will need to know what components are on the network, so that the tech has an idea of where to begin the trouble shooting process. One other comment... There's some debate about the number of IP addresses needed from the ISP. If you want to "initiate contact from the outside world" to a PC on your home network, you will need an IP address for each computer. I.e., if you had one computer as a web server and another computer as an e-mail server, typically, you will need two different IP addresses for the two different machines (there is a way around this, but it's technical and beyond the purpose of the discussion). In most cases, a home user does not want the outside world to be able to contact a computer in his home (i.e, exposure to hackers, etc.). The perfect scenario would be NOT to have an IP address at all. Well, this is technically impossible, so the next best thing is to "hide" the one "required" address, and this is why a firewall is vitally important. The purpose of a firewall is to hide your internet address (among many other more sophisticated tasks). Even without a firewall, using NAT is very good protection. NAT (network address translation) allows virtually unlimited IP addresses on one side of the router (LAN or inside) to communicate through a single address on the other side of the router (WAN or outside address). A hacker may find your router's WAN address, but he typically will not know how to communicate with the PCs on the LAN side of the router (many hackers are unsophisticated "script kiddies" and the more sophisticated hackers who know how to defeat NAT will typically be after bigger targets). Adding a firewall to NAT increases protection by making your WAN IP invisible to the outside world (script kiddies will have a hard time even finding your router before facing NAT protection). In addition, many firewalls have "counter measures" to the tricks that sophisticated hackers will use to defeat NAT protection, or attack an "invisible" IP address. To sum up, most home users do not need more than one outside address regardless of the number of PCs inside the house. Connecting to the internet without a firewall or at a minimum, NAT, is asking for trouble; you will get hacked--it's just a matter of time. If a provider did not allow the use of a router, I would not use that provider (or if had no choice, would disregard the rule). Relating this to trading: common hacks are trojans that allow the hacker to see your desktop and everything you do on it, and also to control your PC just as if they were sitting in front of it. Other trojans capture keystrokes. I'm sure you can imagine the possibilities... Get a firewall router if you don't have one already, and if you need tech support, tell them what you're using to connect ONE PC to the internet (hard wire or wireless, router, etc.). Hope this helps.
Just remember the simple rule. High speed any form Cable/DSL You need to have a router to secure you system Damm the ISP. You have the reply "for security u need one router." When I open ports on my firewall I see the pcs' infected with virus busrting / sending probing signals without even the knowledge of the owner. So if you want to use you PC for a usefull purpose, you must have a NAT router. Good luck with your trading