Add some notes on how to make telnetd actually work

1 files changed, 36 insertions, 2 deletions

diff --git a/networking/Config.in b/networking/Config.in
index a7cef41bf..42176f050 100644
--- a/networking/Config.in
+++ b/networking/Config.in
@@ -492,11 +492,45 @@ config CONFIG_FEATURE_TELNET_AUTOLOGIN
 config CONFIG_TELNETD
         bool "telnetd"
         default n
+        select CONFIG_LOGIN
         help
           A daemon for the TELNET protocol, allowing you to log onto the host
           running the daemon.  Please keep in mind that the TELNET protocol
-          sends passwords in plain text.  If you can't afford the space for
-          any SSH daemon and you trust your network, you may say 'y' here.
+          sends passwords in plain text.  If you can't afford the space for an
+          SSH daemon and you trust your network, you may say 'y' here.  As a
+          more secure alternative, you should seriously consider installing the
+          very small Dropbear SSH daemon instead:
+                http://matt.ucc.asn.au/dropbear/dropbear.html
+
+          Note that for busybox telnetd to work you need several things:
+          First of all, your kernel needs:
+                  CONFIG_UNIX98_PTYS=y
+                  CONFIG_DEVPTS_FS=y
+
+          Next, you need a /dev/pts directory on your root filesystem:
+
+                  $ ls -ld /dev/pts
+                  drwxr-xr-x  2 root root 0 Sep 23 13:21 /dev/pts/
+
+          Next you need the pseudo terminal master multiplexer /dev/ptmx:
+
+                  $ ls -la /dev/ptmx
+                  crw-rw-rw-  1 root tty 5, 2 Sep 23 13:55 /dev/ptmx
+
+          Any /dev/ttyp[0-9]* files you may have can be removed.
+          Next, you need to mount the devpts filesystem on /dev/pts using:
+
+                  mount -t devpts devpts /dev/pts
+
+          You need to be sure that Busybox has CONFIG_LOGIN and
+          CONFIG_FEATURE_SUID enabled.  And finally, you should make
+          certain that Busybox has been installed setuid root:
+
+                chown root.root /bin/busybox
+                chmod 4755 /bin/busybox
+
+          with all that done, telnetd _should_ work....
+
 
 config CONFIG_FEATURE_TELNETD_INETD
         bool "  Support call from inetd only"