So I have a system using ZeroMQ as the message controller and because it doesn't allow you to find information about a clients address that is connecting or sending messages I need to pass in self identifying information containing port and ip address of the node. However I'm not sure the best way of doing this.
I'm stuck because if they connect using an internal ip address for the network I would obviously need to use that ip address but if its going over WAN then I need the public ip address. What is the best way of communicating the ip address of the machine without knowing whether or not you are connecting to a local machine or a machine over WAN
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My computer is using Wi-Fi provided by a tplink router.
I am using a website to get my IP, https://www.whatismyip.com.
My code is fine, because I can connect to the socket in my own computer by using 127.0.0.1.
Here is my code from https://www.geeksforgeeks.org/socket-programming-cc/amp/
But I don't know why my friend can't connect to my socket using the IP I get from the website.
I wonder, do I need to set up something in my router, or am I using the wrong code?
What you get from whatismyip.com is your public IP address. Your computer is probably behind a NAT/PAT (Network Address Translation / Port Address Translation), meaning your machine has a private IP address that gets translated by your router/firewall into the public one displayed by whatismyip.com
You have two solutions:
Get a public IP address from your Internet provider, and disable NAT on your router (probably you'll need help for this).
Configure port forwarding on your router so that it forwards traffic on your public IP address to a given port on your machine.
I coded a TCP/IP Chat Server/Client in C/C++ that works perfectly in my local network and with several clients connected to it. It does not work when the Server is in a different network to the client. I coded time ago the same tool in Python and the same happened.
Is there any way of solving this? Without port forwarding, that is the most common solution.
I could only find this: Android server concept confusion. How to connect TCP chat app on different networks but I could not understand it.
NOTE: I have just find a sample program (server) that works when it is on a different network; http://www.codeproject.com/Articles/1891/Beginning-Winsock-Programming-Simple-TCP-server
You have three choices:
1) NAT penetration. Both devices simultaneously attempt to exchange data with each other, tricking each person's router into thinking that it's replying. For this to work, you each need each other's public IP address and if you need any features from TCP, you need to implement them yourself.
2) Public rendezvous server. Both devices automatically connect to a server on an unNATed network. The server knows the public IP address of every client that connects to it, so it can route your data to the client with the correct public IP.
3) Some combination of 1 and 2. Here, a public server is used to facilitate NAT penetration and eliminate the need for manual coordination. Your friend registers with the public server and the public server tells him your public IP address and facilitates NAT penetration.
In local network addresses of devices doesn't change offently. Yo can reach the computer by only defining the local address. On the other hand, if you want to communicate with a device in different network yoou should know its public IP and should define a routing to the port.
If you have a server with static IP or known IP you can reach it. You can store the IP addresses of clients dynamically in this server. Write a program that inform the IP of host computer to the server. In that way, you can store the IP addresses even they change oftenly.
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.
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.
I have been trying to get the IP of a person on my network, so I tried pinging them and finding their ip on my network site, but it didn't give me their WAN ip. Please help.
if the client is in your network you will probably stay in your LAN - therefore you will get the response from the private IP of course.
the WAN IP is only used when the client tries to access some IP on a public range.
one option is to ask the client to visit something like http://www.whatismyip.com/ and tell you the output or host a service yourself that is doing something similar.
I am trying to find a way that I can effectively change the IP and netmask of the computer that my programs are running on. I have to be able to maintain communications with a "box" that the user has access to and can change the IP of that box (but not that of the Linux host). Luckily the box broadcasts its IP over a multicast address. I am able to read that address and communicate to whatever IP the box is broadcasting. However, my problem is that when the box changes IPs outside of the subnet of the Linux host, I lose connectivity (as I would expect to happen).
As a result, I need a quick and dirty way to to change the IP and netmask of the Linux host when it detects that the IP being broadcast is outside it's subnet. I am aware that I can modify/edit the /etc/networking/interfaces file, but I was hoping to have something "live" where I wouldn't need to restart the networking interface or Linux host. Additionally, I would like to maintain all sockets that I have currently open during the change. My main issue is that I have a slew of connections run by other applications that cannot be corrupted as a result of the IP changeover. Also, if possible, I'd like to avoid having to redo having to run the multicast route add command for Linux after the host IP changeover.
Is there anything that I can do to satisfy these requirements? Thanks.
You don't want to change the IP address of the interface, you want to add an additional IP address and subnet to the interface. Search your Linux system documentation for IP Alias functionality.
Here's the HOWTO.