Solaris PPP 4.0 Basics

Solaris PPP 4.0 implements the Point-to-Point Protocol (PPP), a data link protocol, which is a member of the TCP/IP protocol suite. PPP describes how data is transmitted between two endpoint machines, over communications media such as telephone lines.

Since the early 1990s, PPP has been a widely used Internet standard for sending datagrams over a communications link. The PPP standard is described in RFC 1661 by the Point-to-Point Working Group of the Internet Engineering Task Force (IETF). PPP is commonly used when remote computers call an Internet service provider (ISP) or a corporate server that is configured to receive incoming calls.

Solaris PPP 4.0 is based on the publicly available Australian National University (ANU) PPP–2.4 and implements the PPP standard. Both asynchronous and synchronous PPP links are supported.

Solaris PPP 4.0 Compatibility

Various versions of standard PPP are available and in wide use throughout the Internet community. ANU PPP-2.4 is a popular choice for Linux, Tru64 UNIX,and all three major BSD variants:

• FreeBSD

• OpenBSD

• NetBSD

Solaris PPP 4.0 brings the highly configurable features of ANU PPP-2.4 to machines that run the Solaris operating system. Machines that run Solaris PPP 4.0 can easily set up PPP links to any machine that runs an implementation of standard PPP.

Some non-ANU-based PPP implementations that successfully interoperate with Solaris PPP 4.0 include the following:

• Solaris PPP, also known as asppp, available with the Solaris 2.4 through Solaris 8 releases

• Solstice^TM PPP 3.0.1

• Microsoft Windows 98 DUN

• Cisco IOS 12.0 (synchronous)

Which Version of Solaris PPP to Use

Starting with the Solaris 9 release, Solaris PPP 4.0 is the PPP implementation that is supported. The Solaris 9 release and the Solaris 10 release do not include the earlier Asynchronous Solaris PPP (asppp) software. For more information, refer to the following:

• Chapter 23, Migrating From Asynchronous Solaris PPP to Solaris PPP 4.0 (Tasks)

• Solaris 8 System Administrator Collection at http://docs.sun.com

Why Use Solaris PPP 4.0?

If you currently use asppp, consider migrating to Solaris PPP 4.0. Note the following differences between the two Solaris PPP technologies:

• Transfer modes

  asppp supports asynchronous communications only. Solaris PPP 4.0 supports both asynchronous communications and synchronous communications.

• Configuration process

  Setting up asppp requires configuring the asppp.cf configuration file, three UUCP files, and the ifconfig command. Moreover, you have to preconfigure interfaces for all users who might log in to a machine.

  Setting up Solaris PPP 4.0 requires defining options for the PPP configuration files, or issuing the pppd command with options. You can also use a combination of both the configuration file and command-line methods. Solaris PPP dynamically creates and removes interfaces. You do not have to directly configure PPP interfaces for each user.

• Solaris PPP 4.0 features not available from asppp

  • MS-CHAPv1 and MS-CHAPv2 authentication

  • PPP over Ethernet (PPPoE), to support ADSL bridges

  • PAM authentication

  • Plug-in modules

  • IPv6 addressing

  • Data compression that uses Deflate or BSD compress

  • Microsoft client-side callback support

Solaris PPP 4.0 Upgrade Path

If you are converting an existing asppp configuration to Solaris PPP 4.0, you can use the translation script that is provided with this release. For complete instructions, refer to How to Convert From asppp to Solaris PPP 4.0.

Where to Go for More Information About PPP

Many resources with information about PPP can be found in print and online. The following subsections give some suggestions.

Professional Reference Books About PPP

For more information about widely used PPP implementations, including ANU PPP, refer to the following books:

• Carlson, James. PPP Design, Implementation, and Debugging. 2nd ed. Addison-Wesley, 2000.

• Sun, Andrew. Using and Managing PPP. O'Reilly & Associates, 1999.

Web Sites About PPP

Go to the following web sites for general information about PPP:

• For technical information, FAQs, discussions about Solaris system administration, and earlier versions of PPP, go to Sun Microsystems' system administrators' resource, http://www.sun.com/bigadmin/home/index.html.

• For modem configuration and advice about many different implementations of PPP, refer to Stokely Consulting's Web Project Management & Software Development web site: http://www.stokely.com/unix.serial.port.resources/ppp.slip.html.

Requests for Comments (RFCs) About PPP

Some useful Internet RFCs about PPP include the following:

• 1661 and 1662, which describe the major features of PPP

• 1334, which describes authentication protocols, such as Password Authentication Protocol (PAP) and Challenge-Handshake Authentication Protocol (CHAP)

• 1332, an informational RFC that describes PPP over Ethernet (PPPoE)

To obtain copies of PPP RFCs, specify the number of the RFC on the IETF RFC web page at http://www.ietf.org/rfc.html.

Man Pages About PPP

For technical details about the Solaris PPP 4.0 implementation, refer to the following man pages:

• pppd(1M)

• chat(1M)

• pppstats(1M)

• pppoec(1M)

• pppoed(1M)

• sppptun(1M)

• snoop(1M)

Also, see the man page for pppdump(1M). You can find the PPP-related man pages by using the man command.