--- netkit-telnet-0.17/telnetd/telnetd.8.nodns	2000-07-31 01:57:10.000000000 +0200

+++ netkit-telnet-0.17/telnetd/telnetd.8	2007-04-13 10:58:27.000000000 +0200

@@ -123,6 +123,8 @@

 .Xr login 1

 program.

 .El

+.It Fl c

+This option disables reverse dns checking. Of course that security is lower with this option

 .It Fl D Ar debugmode

 This option may be used for debugging purposes.  This allows

 .Nm telnetd

--- netkit-telnet-0.17/telnetd/telnetd.c.nodns	2007-04-13 10:49:57.000000000 +0200

+++ netkit-telnet-0.17/telnetd/telnetd.c	2007-04-13 10:49:57.000000000 +0200

@@ -83,6 +83,7 @@

 int debug = 0;

 int keepalive = 1;

+int nodns = 0;

 char *loginprg = _PATH_LOGIN;

 char *progname;

@@ -111,7 +112,7 @@

 	progname = *argv;

-	while ((ch = getopt(argc, argv, "d:a:e:lhnr:I:D:B:sS:a:X:L:")) != EOF) {

+	while ((ch = getopt(argc, argv, "cd:a:e:lhnr:I:D:B:sS:a:X:L:")) != EOF) {

 		switch(ch) {

 #ifdef	AUTHENTICATE

@@ -147,7 +148,9 @@

 			bftpd++;

 			break;

 #endif /* BFTPDAEMON */

-

+		case 'c':

+			nodns++;

+			break;

 		case 'd':

 			if (strcmp(optarg, "ebug") == 0) {

 				debug++;

@@ -652,6 +655,9 @@

 	char namebuf[255];

 	error = getnameinfo(who, wholen, namebuf, sizeof(namebuf), NULL, 0, 0);

+

+	if ((error == EAI_AGAIN) && nodns)

+		error = getnameinfo(who, wholen, namebuf, sizeof(namebuf), NULL, 0, NI_NUMERICHOST);

 	if (error) {

 		perror("getnameinfo: localhost");

@@ -688,7 +694,10 @@

 		hints.ai_socktype = SOCK_STREAM;

 		hints.ai_flags = AI_ADDRCONFIG;

-		gethostname(host_name, sizeof(host_name));

+		if(nodns)

+			sprintf(host_name, "localhost", sizeof(host_name));

+		else

+			gethostname(host_name, sizeof(host_name));

 		if ((e = getaddrinfo(host_name, NULL, &hints, &res)) != 0) {

 			perror("getaddrinfo: localhost");

 			perror(gai_strerror(e));