CODEWITHSUNDEEP
c++network-programmingip-address
user3408137
user3408137

Reputation: 21

Get ip address of computer on network c++

I am trying to make a C++ program in Windows that will output all of the ip addresses on the network to a text file but I have not been able to find anything useful online for other computers on the network. I figured out how to query the registry and find the local ip but I dont even know where to start to find other ip addresses. I don't want a copy-paste cookie cutter code because I want to learn how it works so if I could just get a link or a book that will guide me in the right direction that would be great.

Upvotes: 1

Views: 1518

Answers (1)

Mark H
Mark H

Reputation: 13897

For what purpose do you want to gain these IPs anyway?

I suspect what you're looking for is a way to obtain all possible IPs in a given subnet, which can be done quite trivially for say, IPv4. You simply take the IP address of your machine or router, and apply the subnet mask to it using bitwise and. (eg, 192.168.1.20 & 255.255.255.0 = 192.168.1.0, called the base, or network address). The valid hosts in this network are basically all of the bits which are zero in the subnet mask (255 in the previous example). This means the range 192.168.1.0 - 192.168.1.255 (exclusive, as the network address and broadcast address are not valid IP addresses of hosts in the network) are valid IP addresses of hosts.

There's no truly reliable way for any machine on the network other than the router to obtain specific information as to which of these addresses are in use though, as the interaction between machines on a network is meant to be voluntary, not implicit. Most machines however are generally running some kind of protocol which enables them to discover each other for purposes like printer and file sharing.

You can attempt to ping each of the possible host addresses in the network, or port scan, or talk to them with some protocol they might know. Alternatively you can use the broadcast address with a known protocol to ask all machines on the network to report back to you, and if they're running some software which talks that protocol, they'll respond with their own addresses.

Upvotes: 1

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