-out which operating system you are using and creates symbolic links to
-the appropriate makefiles. You then run `make' to compile the
-user-level code, and (as root) `make install' to install the
-user-level programs pppd, chat and pppstats.
-
-The procedures for installing the kernel code vary from system to
-system. On some systems, the kernel code can be loaded into a running
-kernel using a `modload' facility. On others, the kernel image has to
-be recompiled and the system rebooted. See the README.* files for
-details.
-
-(Unfortunately, AIX 4 is no longer supported, since I don't have a
-maintainer for the AIX 4 port. If you want to volunteer, contact me.)
-
-
-What's new in ppp-2.3.
-**********************
-
-* Demand-dialling. Pppd now has a mode where it will establish the
-network interface immediately when it starts, but not actually bring
-the link up until it sees some data to be sent.
-
-* Idle timeout. Pppd will optionally terminate the link if no data
-packets are sent or received within a certain time interval.
-
-* Pppd now runs the /etc/ppp/auth-up script, if it exists, when the
-peer successfully authenticates itself, and /etc/ppp/auth-down when
-the connection is subsequently terminated.
-
-* A new packet compression scheme, Deflate, has been implemented.
-This uses the same compression method as `gzip'. This method is free
-of patent or copyright restrictions, and it achieves better
-compression than BSD-Compress. It does consume more CPU cycles for
-compression than BSD-Compress, but this won't be a problem for links
-running at 100kbit/s or less.
-
-* There is now no code in this distribution which is covered by Brad
-Clements' restrictive copyright notice. The STREAMS modules for SunOS
-and OSF/1 have been rewritten, based on the Solaris 2 modules, which
-were written from scratch without any Clements code.
-
-* Pppstats has been reworked to clean up the output format somewhat.
-It also has a new -d option which displays data rate in kbyte/s for
-those columns which would normally display bytes.
-
-
-Patents.
-********
-
-The BSD-Compress algorithm used for packet compression is the same as
-that used in the Unix "compress" command. It is apparently covered by
-U.S. patents 4,814,746 (owned by IBM) and 4,558,302 (owned by Unisys),
-and corresponding patents in various other countries (but not
-Australia). If this is of concern, you can build the package without
-including BSD-Compress. To do this, edit net/ppp-comp.h to change the
-definition of DO_BSD_COMPRESS to 0. The bsd-comp.c files are then no
-longer needed, so the references to bsd-comp.o may optionally be
-removed from the Makefiles.
+out which operating system you are using and creates the appropriate
+makefiles. You then run `make' to compile the user-level code, and
+(as root) `make install' to install the user-level programs pppd, chat
+and pppstats.
+
+N.B. Since 2.3.0, leaving the permitted IP addresses column of the
+pap-secrets or chap-secrets file empty means that no addresses are
+permitted. You need to put a "*" in that column to allow the peer to
+use any IP address. (This only applies where the peer is
+authenticating itself to you, of course.)
+
+
+What's new in ppp-2.5.1
+***********************
+
+* Pppd can now measure and log the round-trip time (RTT) of LCP
+ echo-requests and record them in a binary file structured as a
+ circular buffer. Other programs or scripts can examine the file and
+ provide real-time statistics on link latency. This is enabled by a
+ new "lcp-rtt-file" option.
+
+* New scripts net-init, net-pre-up and net-down are executed in the
+ process of bringing the network interface up and down. They provide
+ additional, more deterministic ways for pppd to interact with the
+ rest of the networking configuration.
+
+* Pppd will now create the directory for the TDB connection database
+ if it doesn't already exist.
+
+* Various other bug fixes and minor enhancements.
+
+
+What was new in ppp-2.5.0.
+**************************
+
+The 2.5.0 release is a major release of pppd which contains breaking
+changes for third-party plugins, a complete revamp of the build-system
+and that allows for flexibility of configuring features as needed.
+
+In Summary:
+* Support for PEAP authentication by Eivind Næss and Rustam Kovhaev
+* Support for loading PKCS12 certificate envelopes
+* Adoption of GNU Autoconf / Automake build environment, by Eivind Næss
+ and others.
+* Support for pkgconfig tool has been added by Eivind Næss.
+* Bunch of fixes and cleanup to PPPoE and IPv6 support by Pali Rohár.
+* Major revision to PPPD's Plugin API by Eivind Næss.
+ - Defines in which describes what features was included in pppd
+ - Functions now prefixed with explicit ppp_* to indicate that
+ pppd functions being called.
+ - Header files were renamed to better align with their features,
+ and now use proper include guards
+ - A pppdconf.h file is supplied to allow third-party modules to use
+ the same feature defines pppd was compiled with.
+ - No extern declarations of internal variable names of pppd,
+ continued use of these extern variables are considered
+ unstable.
+* Lots of internal fixes and cleanups for Radius and PPPoE by Jaco Kroon
+* Dropped IPX support, as Linux has dropped support in version 5.15
+ for this protocol.
+* Many more fixes and cleanups.
+* Pppd is no longer installed setuid-root.
+* New pppd options:
+ - ipv6cp-noremote, ipv6cp-nosend, ipv6cp-use-remotenumber,
+ ipv6-up-script, ipv6-down-script
+ - -v, show-options
+ - usepeerwins, ipcp-no-address, ipcp-no-addresses, nosendip
+* On Linux, any baud rate can be set on a serial port provided the
+ kernel serial driver supports that.
+
+Note that if you have built and installed previous versions of this
+package and you want to continue having configuration and TDB files in
+/etc/ppp, you will need to use the --sysconfdir option to ./configure.
+
+For a list of the changes made during the 2.4 series releases of this
+package, see the Changes-2.4 file.
+
+
+Compression methods.
+********************
+
+This package supports two packet compression methods: Deflate and
+BSD-Compress. Other compression methods which are in common use
+include Predictor, LZS, and MPPC. These methods are not supported for
+two reasons - they are patent-encumbered, and they cause some packets
+to expand slightly, which pppd doesn't currently allow for.
+BSD-Compress and Deflate (which uses the same algorithm as gzip) don't
+ever expand packets.