Find all IP addresses on router?

IP addresses and their functions?

• I understand the basics of IP addresses and just need to clarify a few things regarding Internal IP, External, the Router Address and Subnet Mask. I will start with the easiest - the External IP - that which exists on the 'net-wards' side of your connection (beyond internal server/router/LAN and any firewall), this is basically the 'postal address' for all the pc's 'digital mail i.e. all traffic between internet sites, external / net-linked server clients etc Have I missed anything important here? Now I know what my Internal IP is, that it has no connection to the outside world and how to find it using command line etc. I have just one pc (in my home 'network), linked to a router (with hardware-based firewall) on dhcp IPv4, so is my Internal IP the (private) address of my PC? ie the actual machine id itself? Router Address - this also appears to be called Default Gateway? Am I also right in thinking the Router IP Address is part of the private (LAN) network and is only viewable to those devices existing within my private network (pc, wireless laptop etc)? Subnet Mask, Googled - didnt make a lot of sense, apart from it role in sub-networks - is this referring to LAN networks, or a subdivision of the external mainframe within the internet? Is it a standard address, or user specific? DHCP - I thought every time you booted up/established a new 'net connection that the dynamic host refreshed and the external ip assigned a new address at random, I've seen that a dynamic host it can also remain 'static' (with a small 's') for longer periods, how often does this change? I also notice that when using reverse ip tracing software, your external ip geographically pinpointed to your ISP's local distribution point / 'junction box', is it true that your computer's location can be traced directly to your front door if necessary? Cheers in advance Adrian

• Answer:

  > so is my Internal IP the (private) address of my PC? More or less. An IP address is the address of a network interface on a particular network. So if you have a laptop with a wi-fi network connection and an ethernet connect, then it will have two ip addresses. If the two connections are on the same network, then those two ip addresses will both be on the same network. Your router will have at least two network interfaces. One of them one your local network (LAN) and one on the Internet (which is just another network, even if it is a huge one that spans the globe). Each interface will have an IP address, the one on the Interent will be the external IP address you refer to. > Router Address - this also appears to be called Default Gateway? The job of a router is to join two networks together so that computers attached to one can talk to computers attached to the other. The "default gateway" is the name given to the router that a computer will ask to relay data to machines on a different network by default (i.e. unless overridden). So for the typical home network, they are the same thing. > Am I also right in thinking the Router IP Address is part of the private (LAN) network and is only viewable to those devices existing within my private network (pc, wireless laptop etc)? The router has to have ip addresses on multiple networks for it to do its job. The ip address it has on the LAN will only be visible to other machines on the LAN (unless you have some routing system set up to make it visible to machines on other networks, which you won't do with your set up). > Subnet Mask This is just a way of dividing networks up so that ip addresses can be allocated to specific networks and data can be routed between them. You don't need to worry about it for your network. > DHCP - I thought every time you booted up/established a new 'net connection that the dynamic host refreshed and the external ip assigned a new address at random, I've seen that a dynamic host it can also remain 'static' (with a small 's') for longer periods, how often does this change? You are right up to the "at random" point. IP addresses can be allocated however the DHCP server likes. Most will try to allocate the same address when a machine reconnects. > I also notice that when using reverse ip tracing software, your external ip geographically pinpointed to your ISP's local distribution point / 'junction box', is it true that your computer's location can be traced directly to your front door if necessary? Your ISP will have records of which IP addresses are allocated to which customers and when. If it is needed, they can link the IP address with your customer information and thus your location, but this is private information and a court order will be needed for anyone outside the ISP to get the information. Publicly available GeoIP databases are accurate only to the level you've seen.