Very Computer

I'm working on a GUI FTP client application in Java. In order to
implement the PORT command I need the IP address of the client machine
i.e. an IP address that the FTP host can use to connect to a port on the
client machine. The Java method "getLocal Host()" just returns
127.0.0.1".  I'm looking for some way to get this, hopefully a UNIX
command that would return the IP number.

Thanks Clu

: I'm working on a GUI FTP client application in Java. In order to
: implement the PORT command I need the IP address of the client machine
: i.e. an IP address that the FTP host can use to connect to a port on the
: client machine. The Java method "getLocal Host()" just returns
: 127.0.0.1".  I'm looking for some way to get this, hopefully a UNIX
: command that would return the IP number.

: Thanks Clu

in C the following program will obtain all of the IP addresses
available for the machine:

/* on Solaris build using: cc -o getip getip.c -lxnet */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>

int
main(int argc, char *argv[])
{
        struct hostent *he;
        char   hn[256];
        int    i = 0;
        struct in_addr *addr;

        /* get our hostname */

        if(gethostname(hn, 256) != 0)
        {
                perror("gethostname");
                return 1;
        }

        printf("host: %s\n", hn);

        /* enumerate addresses available on this host */
        he = gethostbyname(hn);
        if(he)
        {
                while(he->h_addr_list[i])
                {
                        addr = (struct in_addr *) he->h_addr_list[i];
                        printf("  %s\n", inet_ntoa(*addr));
                        i++;
                }
        }
        else
                perror("gethostbyname");

        return 0;

Quote:}

"UNIX _IS_ user friendly, its just picky about who its friends are."

It might be possible to obtain this through JNI (although it is a bit
tricky.)

The procedure would be something like this: pass the socket descriptor
through JNI, use getsockname(), extract the address from 'struct sockaddr
*' (by casting it to 'struct sockaddr_in *' first), and return this
address in some format you find appropriate.

Quote:> I'm working on a GUI FTP client application in Java. In order to
> implement the PORT command I need the IP address of the client machine
> i.e. an IP address that the FTP host can use to connect to a port on
the
> client machine. The Java method "getLocal Host()" just returns
> 127.0.0.1".  I'm looking for some way to get this, hopefully a UNIX
> command that would return the IP number.

Why can't you use the original socket on the server, the one the
client opened, and use getInetAddress() to extract the IP address from
that.

JC

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Pete M.