diff --git a/appl/telnet/libtelnet/kerberos5.c b/appl/telnet/libtelnet/kerberos5.c
index cf4094cb2..1f3893aaf 100644
--- a/appl/telnet/libtelnet/kerberos5.c
+++ b/appl/telnet/libtelnet/kerberos5.c
@@ -277,6 +277,7 @@ kerberos5_is(Authenticator *ap, unsigned char *data, int cnt)
     krb5_data outbuf;
     krb5_keyblock *key_block;
     char *name;
+    krb5_principal server;
     int zero = 0;
 
     if (cnt-- < 1)
@@ -311,14 +312,30 @@ kerberos5_is(Authenticator *ap, unsigned char *data, int cnt)
 	    return;
 	}
 
+	ret = krb5_sock_to_principal (context,
+				      0,
+				      "host",
+				      KRB5_NT_SRV_HST,
+				      &server);
+	if (ret) {
+	    Data(ap, KRB_REJECT, "krb5_sock_to_principal failed", -1);
+	    auth_finished(ap, AUTH_REJECT);
+	    if (auth_debug_mode)
+		printf("Kerberos V5: "
+		       "krb5_sock_to_principal failed (%s)\r\n",
+		       krb5_get_err_text(context, ret));
+	    return;
+	}
+
 	ret = krb5_rd_req(context,
 			  &auth_context,
 			  &auth, 
-			  NULL,
+			  server,
 			  NULL,
 			  NULL,
 			  &ticket);
 
+	krb5_free_principal (context, server);
 	if (ret) {
 	    char *errbuf;