this may have been hit on already but according to my knowledge as a tech: ISP decides static ip or DHCP configuration not your modem. static ip is usually for business. otherwise the internet would be tapped out of all class IPs, awaiting the implementation of IPv6. IPaddresses can give a cracker a starting point on where to look for vulnerabilities like and open port to send a file. ISPs lease Ip addresses for a certain time and change them regularly using DHCP, most consumers ips are DHCP configured. dont really wanna talk about dedicated stuff so… firewalls do hide ips, filter ports and packets (may require some tweaking) but do not encrypt. ips can be obtained by interceptors with packet sniffing software and a NIC in promiscuous mode but this requires a connection on a network whether it be an unsecured wireless net or a wired. email progs like outlook can get ips but they change regularly so who cares. my advise, get a router that supports NAT. wireless? use WPA encryption at least and maybe throw in mac address filtering, this is configured on your routers interface. ZONEALARM is a free, good, and basic firewall that will have no problem blocking remote access unless you allow it (this is the real threat) and will even tell you when you are being pinged or if someone is trying to telnet you. depending on your operating system, unless you ask for remote assistance no one can access your PC remotely. however, if i installed GoToMyPC on your computer and maybe later got in and threw a key logger onto you system then i can do real harm. a trojan can act in the same manner as GTMPC and usually hide awaiting a command from a remote user. dont download the wrong game or porn, check certificates for revokation. might get a backdoor trojan and boom you now have a RAT (remote access trojan) trojan. a backdoor trojan opens a port which could allow a cracker to transfer a larger file thru the port that is the RAT client/server prog. and the phun begins. then you get to troubleshoot, run antivirus, restore your computer, take out your CMOS battery, reload your OS, whatever. its a lot of work. just get a router and setup some good old security. you know, a strong password using capital/lowercase/alphanumeric/ special characters. configure NAT on your router to hide your PCs IP, block port ranges with your router and or PC firewall. let me guess, since i didnt read ALL of the replies, you guys already said all this. sheesh, why didnt you stop me! i was on a roll.