Recently ive noticed a strange thing:

while passing a pointer of any ip address e.g. 100.10.10.10 to
gethostbyname function it doesnt return a NULL pointer  (as it should) even 
though that address does NOT exist. ( the program is run on a standalone
machine with no DNS , no named , and has no "100.10.10.10" entry in 
/etc/hosts)

Lets say: 

struct hostent *hostp;

hostp = gethostbyname ( argv [1] ) ; /* where argv[1] is "100.10.10.10"
printf("Host name %s\t Host address %s\n", hostp->h_name ,
			inet_ntoa( hostp->h_addr) ); 

--> It would print on stdout: 

   Host name 100.10.10.10    Host address 100.10.10.10

Is it a bug or a feature ?????

Normally gethostbyname() should only accepts hostnames ( not host 
addresses ) such as those ones in /etc/hosts ( moon , galaxy and so on)


If i would write:

check.c

main(argc,argv)
int argc;
char *argv[];
{
	struct hostent *hostp;
	unsigned long addr, inet_addr();
	int i;

	for (i=1 ; i<argc ; i++)
        {
		if ( (hostp = gethostbyname( argv[i] )) == NULL)
		{
			addr = inet_addr ( argv[i] );
			if ( (hostp = gethostbyaddr( &addr, sizeof(struct 
			 in_addr) , AF_INET ) ) == NULL )
			printf("Host not found \n");
			else 
			....
			(rest of program)
		}
	}
}

and run : ./check 100.10.10.10

it will never reach gethostbyaddr() because gethostbyname() will return
not NULL. 

What about that ??????

gelo.