The ability to remotely SSH into a machine running an Ubuntu LiveCD can come in handy in many situations. The LiveCD supports a large variety of hardware and can be used to troubleshoot system problems on a machine where you have limited or no access. A user with limited skills can easily setup remote access [...]

In C or C++ it is fairly simple to find the IP address of the remote end of a TCP socket.
The following example shows how to do this using the getpeername() and inet_ntoa() system calls.

int sockfd;
int len;
char * hostip;
struct sockaddr_in sin;

len = sizeof(sin);

if (0 != getpeername(sockfd, (struct sockaddr *) &sin, &len))
[...]

You can find the IP address of your system at the command line by using the ifconfig command. The ifconfig command will show you information on all your network interfaces. If no arguments are given ifconfig displays the status of the currently active interfaces.
You have to run this command as root or use [...]

Here is a good way to determine the hostname and IP address of the local machine in C.
You first have to grab the hostname with gethostname().

char hostbuf[256];
gethostname(hostbuf,sizeof(hostbuf));

Take the hostname and use it to grab the hostent struct with gethostbyname().

struct hostent *hostentry;
hostentry = gethostbyname(hostbuf);

Finally you have to take the hostent that is returned and pull out [...]