[Solved] How do my router obtain normal ip address [closed]

Question

I’m not completely following your question. Any IP address assigned to your computer is a real IP address which your computer uses. It may be a private IP address which can be reused in different networks, or it may be a public address which is supposed to be unique in the world (I think this is what you mean). IP addresses are assigned to your computer either by being statically assigned, or being assigned through DHCP.

If you want to know the public IP address assigned to your router, then you can look in your router, or browse one of the websites which will tell you what your public IP address is.

The ISP owns one or more blocks of public IP addresses, and it will assign your router an address via DHCP or PPP. Since some RIRs no longer have nay blocks of public IPv4 addresses to assign to the ISPs, many ISP have started using CGN which will assign private IP addresses to your router. This causes a double-NAT, which causes all kinds of problems.

The ISP does not assign your private IP addresses, you do that. There are three blocks of private IP addresses (10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16) which you can use to assign your private IP addressing. The router manufacturers all used to use 192.168.0.0/24, but in recent years, they have mostly moved to using 192.168.1.0/24. It doesn’t matter which block of private addresses you use.

Your router is running NAT which translates all your private addresses to a single public address (assuming your ISP isn’t using CGN). In order to reach your LAN from the public Internet, you will need to set up NAT forwarding rules to be able to translate from the public IP address to one of your private IP addresses. This is known as port forwarding, and it is done by TCP or UDP port number, and you can only have one TCP or UDP port reach one private IP address inside your LAN. For instance, if you run a web server (nominally port 80), you can configure your router to forward any traffic arriving on the public address using port 80 to the web server inside your LAN.

Accepted Answer

I’m not completely following your question. Any IP address assigned to your computer is a real IP address which your computer uses. It may be a private IP address which can be reused in different networks, or it may be a public address which is supposed to be unique in the world (I think this is what you mean). IP addresses are assigned to your computer either by being statically assigned, or being assigned through DHCP.

If you want to know the public IP address assigned to your router, then you can look in your router, or browse one of the websites which will tell you what your public IP address is.

The ISP owns one or more blocks of public IP addresses, and it will assign your router an address via DHCP or PPP. Since some RIRs no longer have nay blocks of public IPv4 addresses to assign to the ISPs, many ISP have started using CGN which will assign private IP addresses to your router. This causes a double-NAT, which causes all kinds of problems.

The ISP does not assign your private IP addresses, you do that. There are three blocks of private IP addresses (10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16) which you can use to assign your private IP addressing. The router manufacturers all used to use 192.168.0.0/24, but in recent years, they have mostly moved to using 192.168.1.0/24. It doesn’t matter which block of private addresses you use.

Your router is running NAT which translates all your private addresses to a single public address (assuming your ISP isn’t using CGN). In order to reach your LAN from the public Internet, you will need to set up NAT forwarding rules to be able to translate from the public IP address to one of your private IP addresses. This is known as port forwarding, and it is done by TCP or UDP port number, and you can only have one TCP or UDP port reach one private IP address inside your LAN. For instance, if you run a web server (nominally port 80), you can configure your router to forward any traffic arriving on the public address using port 80 to the web server inside your LAN.