Binding to port 162?

Question

I'm trying to write code that will bind to port 162. I'm able to do this
if I'm root, however if I'm another user this fails. The user account
I'm trying this under has the same group memberships as root. Could you
please let me know what I need to do to be able to do this?
Thanks in advance,
Dave Zeltserman
[email protected]

Answer 1

Try this sample code as root:
/* compile using cc test.c -lnsl */
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <fcntl.h>
#include <netdb.h>
#include <stropts.h>
#include <tiuser.h>
#include <netinet/in.h>
#include <signal.h>
#define BUFSIZE 256
#define PORT 162
extern int t_errno; /* TLI globle errno */
main()
int fd, flags; /* Transport endpoint */
char buffer[BUFSIZE]; /* Data buffer */
struct t_call call;              / TLI call request */
struct t_bind bind;              / TLI bind request */
struct sockaddr_in server;
if ((fd = t_open("/dev/tcp", O_RDWR, (struct t_info *)NULL)) < 0)
t_error("t_open failed for fd");
exit(1);
/* Set up bind structures */
if ((bind = (struct t_bind *)t_alloc(fd, T_BIND, T_ALL)) == NULL)
t_error("t_alloc of t_bind struct failed");
exit(1);
memset((char *)&server, 0, sizeof(server));
server.sin_family = AF_INET;
server.sin_port = htons(PORT);
server.sin_addr.s_addr = htonl(INADDR_ANY);
bind->addr.maxlen = sizeof(server);
bind->addr.len = sizeof(server);
bind->addr.buf = (char *)&server;
bind->qlen = 5;
if (t_bind(fd, bind, bind) < 0)
t_error("t_bind failed for fd");
exit(1);
* Was the correct address bound ?
if (((struct sockaddr_in *)(bind->addr.buf))->sin_port != PORT)
printf("t_bind bound wrong address\n");
printf("Got %d instead of %d.\n", ((struct sockaddr_in *)(bind->addr.buf))->sin_port, PORT);
exit(1);
printf("Got Port %d \n", ((struct sockaddr_in *)(bind->addr.buf))->sin_port);
if ((call = (struct t_call *)t_alloc(fd, T_CALL, T_ALL)) == NULL)
t_error("t_alloc of t_call structure failed");
exit(1);
Output:
# ./a.out
Got Port 162
#