to pppd when using PAP authentication so that it can select the
appropriate secret from /etc/ppp/pap-secrets.
-Microsoft also has a variant of CHAP which they apparently think is
-more secure than standard CHAP because they don't store secrets in
-clear text on the server. However, a bogus client only needs to know
-the encrypted secret to gain access, so the only extra security is
-that the bogus client would need to run something other than Windows.
-There is a client-side implementation of Microsoft's CHAP in ppp-2.3;
-see README.MSCHAP80.
+Microsoft also has a variant of CHAP which uses a different hashing
+arrangement from normal CHAP. There is a client-side implementation
+of Microsoft's CHAP in ppp-2.3; see README.MSCHAP80.
------------------------------------------------------------------------
compressor, simply because it compresses strings of nulls so well that
it has to eat a very large amount of input data to get each byte of
output.
+
+
+------------------------------------------------------------------------
+
+Q: I get messages saying "Unsupported protocol (...) received". What do
+these mean?
+
+A: If you only get one or two when pppd starts negotiating with the
+peer, they mean that the peer wanted to negotiate some PPP protocol
+that pppd doesn't understand. This doesn't represent a problem, it
+simply means that there is some functionality that the peer supports
+that pppd doesn't, so that functionality can't be used.
+
+If you get them sporadically while the link is operating, or if the
+protocol numbers (in parentheses) don't correspond to any valid PPP
+protocol that the peer might be using, then the problem is probably
+that characters are getting corrupted on the receive side, or that
+extra characters are being inserted into the receive stream somehow.
+If this is happening, most packets that get corrupted should get
+discarded by the FCS (Frame Check Sequence, a 16-bit CRC) check, but a
+small number may get through.
+
+One possibility may be that you are receiving broadcast messages on
+the remote system which are being sent over your serial link. Another
+possibility is that your modem is set for XON/XOFF (software) flow
+control and is inserting ^Q and ^S characters into the receive data
+stream.
+
+
+------------------------------------------------------------------------
+
+Q: I get messages saying "Protocol-Reject for unsupported protocol ...".
+What do these mean?
+
+A: This is the other side of the previous question. If characters are
+getting corrupted on the way to the peer, or if your system is
+inserting extra bogus characters into the transmit data stream, the
+peer may send protocol-reject messages to you, resulting in the above
+message (since your pppd doesn't recognize the protocol number
+either.)
+
+
+------------------------------------------------------------------------
+
+Q: I get a message saying something like "ioctl(TIOCSETD): Operation
+not permitted". How do I fix this?
+
+A: This is because pppd is not running as root. If you have not
+installed pppd setuid-root, you will have to be root to run it. If
+you have installed pppd setuid-root and you still get this message, it
+is probably because your shell is using some other copy of pppd than
+the installed one - for example, if you are in the pppd directory
+where you've just built pppd and your $PATH has . before /usr/sbin (or
+wherever pppd gets installed).
+
+
+------------------------------------------------------------------------
+
+Q: Has your package been ported to HP/UX or IRIX or AIX?
+
+A: No. I don't have access to systems running HP/UX or AIX. No-one
+has volunteered to port it to HP/UX. I had someone who did a port for
+AIX 4.x, but who is no longer able to maintain it. And apparently AIX
+3.x is quite different, so it would need a separate port.
+
+IRIX includes a good PPP implementation in the standard distribution,
+as far as I know.
+
+
+------------------------------------------------------------------------
+
+Q: Under SunOS 4, when I try to modload the ppp modules, I get the
+message "can't open /dev/vd: No such device".
+
+A: First check in /dev that there is an entry like this:
+
+crw-r--r-- 1 root 57, 0 Oct 2 1991 vd
+
+If not, make one (mknod /dev/vd c 57 0). If the problem still exists,
+probably your kernel has been configured without the vd driver
+included. The vd driver is needed for loadable module support.
+
+First, identify the config file that was used. When you boot your
+machine, or if you run /etc/dmesg, you'll see a line that looks
+something like this:
+
+SunOS Release 4.1.3_U1 (CAP_XBOX) #7: Thu Mar 21 15:31:56 EST 1996
+ ^^^^^^^^
+ this is the config file name
+
+The config file will be in the /sys/`arch -k`/conf directory (arch -k
+should return sun4m for a SparcStation 10, sun3x for a Sun 3/80,
+etc.). Look in there for a line saying "options VDDRV". If that line
+isn't present (or is commented out), add it (or uncomment it).
+
+You then need to rebuild the kernel as described in the SunOS
+manuals. Basically you need to run config and make like this:
+
+ /usr/etc/config CAP_XBOX
+ cd ../CAP_XBOX
+ make
+
+(replacing the string CAP_XBOX by the name of the config file for your
+kernel, of course).
+
+Then copy the new kernel to /:
+
+ mv /vmunix /vmunix.working
+ cp vmunix /
+
+and reboot. Modload should then work.
+
+
+------------------------------------------------------------------------
+
+Q: I'm running Linux (or NetBSD or FreeBSD), and my system comes with
+PPP already. Should I consider installing this package? Why?
+
+A: The PPP that is already installed in your system is (or is derived
+from) some version of this PPP package. You can find out what version
+of this package is already installed with the command "pppd --help".
+If this is older than the latest version, you may wish to install the
+latest version so that you can take advantage of the new features or
+bug fixes.
+
+
+------------------------------------------------------------------------
+
+Q: I'm running pppd in demand mode, and I find that pppd often dials
+out unnecessarily when I try to make a connection within my local
+machine or with a machine on my local LAN. What can I do about this?
+
+A: Very often the cause of this is that a program is trying to contact
+a nameserver to resolve a hostname, and the nameserver (specified in
+/etc/resolv.conf, usually) is on the far side of the ppp link. You
+can try executing a command such as `ping myhost' (where myhost is the
+name of the local machine, or some other machine on a local LAN), to
+see whether that starts the ppp link. If it does, check the setup of
+your /etc/hosts file to make sure you have the local machine and any
+hosts on your local LAN listed, and /etc/resolv.conf and/or
+/etc/nsswitch.conf files to make sure you resolve hostnames from
+/etc/hosts if possible before trying to contact a nameserver.