--- postfix-2.0.9/src/util/get_hostname.c.orig	2003-04-28 13:15:08.000000000 +0200
+++ postfix-2.0.9/src/util/get_hostname.c	2003-04-28 13:36:47.000000000 +0200
@@ -33,6 +33,7 @@
 #include <sys/param.h>
 #include <string.h>
 #include <unistd.h>
+#include <netdb.h>
 
 #if (MAXHOSTNAMELEN < 256)
 #undef MAXHOSTNAMELEN
@@ -55,6 +56,7 @@
 const char *get_hostname(void)
 {
     char    namebuf[MAXHOSTNAMELEN + 1];
+	struct hostent *hp;
 
     /*
      * The gethostname() call is not (or not yet) in ANSI or POSIX, but it is
@@ -66,9 +68,11 @@
 	if (gethostname(namebuf, sizeof(namebuf)) < 0)
 	    msg_fatal("gethostname: %m");
 	namebuf[MAXHOSTNAMELEN] = 0;
-	if (valid_hostname(namebuf, DO_GRIPE) == 0)
+	if (!(hp = gethostbyname(namebuf)))
+	    msg_fatal("gethostbyname(\"%s\") does not resolve as a fully qualified domain name.", namebuf);
+	if (valid_hostname(hp->h_name, DO_GRIPE) == 0)
 	    msg_fatal("unable to use my own hostname");
-	my_host_name = mystrdup(namebuf);
+	my_host_name = mystrdup(hp->h_name);
     }
     return (my_host_name);
 }