367 lines
14 KiB
Plaintext
367 lines
14 KiB
Plaintext
<!-- $Id: userppp.sgml,v 1.7 1996/05/16 23:18:28 mpp Exp $ -->
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<!-- The FreeBSD Documentation Project -->
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<sect>Setting up user PPP<label id="userppp">
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<p><em>Contributed by &a.nik;<newline>
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28 July 1995</em>.
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<!-- This FAQ/HowTo is intended to get you up and running with
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iijppp, also known as the <em>user level ppp</em> for FreeBSD 2.0.5
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(and above).
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I hope this document turns into a collaborative effort, largely
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because I am not really much of an authority on PPP. I have got
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it working, and want to pass on details of what I did so that
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other people can get it working. But I am not 100% clear on some
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details, so I hope that by writing this and having others
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flesh out some of the information I am going to learn something
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as well.
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-->
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<p>User PPP was introduced to FreeBSD in release 2.0.5 as an
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addition to the existing kernel implementation of PPP. So,
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what is different about this new PPP that warrants its
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addition? To quote from the manual page:
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<quote>
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This is a user process PPP software package. Normally, PPP is
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implemented as a part of the kernel (e.g. as managed by pppd) and
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it is thus somewhat hard to debug and/or modify its behavior. However,
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in this implementation PPP is done as a user process with the help of
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the tunnel device driver (tun).
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</quote>
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In essence, this means that rather than running a PPP daemon, the ppp
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program can be run as and when desired. No PPP interface needs to be
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compiled into the kernel, as the program can use the generic tunnel
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device to to get data into and out of the kernel.
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From here on out, user ppp will be referred to as simply as ppp unless a
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distinction need to be made be it and any other PPP client/server software.
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Unless otherwise stated, all commands in this section should be
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executed as root.
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Parts in this section marked with an asterisk (*) are
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incomplete. Comments and suggestions are appreciated and
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should be submitted to &a.nik;.
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Thanks to Rob Snow <rsnow@txdirect.net> who proved to be a mine of
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useful information when I was first experimenting with user ppp.
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<sect1><heading>Before you start</heading>
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<p>This document assumes you are in roughly this position:
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You have an account with an Internet Service Provider (ISP) which lets you
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use PPP. Further, you have a modem (or other device) connected and
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configured correctly which allows you to connect to your ISP.
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You are going to need the following information to hand:
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<itemize>
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<item>IP address of your ISP's gateway
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<item>Your ISP's netmask setting
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<item>IP addresses of one or more nameservers
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<item>If your ISP allocates you a static IP address and/or hostname then
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you will need that as well. If not, you will need to know from what
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range of IP addresses your allocated IP address will fall in.
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</itemize>
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If you do not have any of this information then contact your ISP and make
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sure they provide it to you.
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As well as this, you may need the files required to recompile
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your kernel. Check <ref id="kernelconfig" name="Kernel
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Configuration"> for more information on how to acquire these.
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In addition, I have assumed that because your connection to the Internet is
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not full time you are not running a name server (<tt>named(8)</tt>).
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<sect1><heading>Building a ppp ready kernel</heading>
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<p>As the description states, ``ppp'' uses the kernel ``tun'' device. It is
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necessary to make sure that your kernel has support for this device compiled
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in.
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To check this, go to your kernel compile directory (probably /sys/i386/conf)
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and examine your kernel configuration file. It needs to have the line
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<tscreen><verb>
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pseudo-device tun 1
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</verb></tscreen>
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in it somewhere. The stock GENERIC kernel has this as standard, so if you
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have not installed a custom kernel you do not have to change anything.
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If your kernel configuration file does not have this line in it then you
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should add the line, re-compile and then re-install the kernel. Boot from
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this new kernel. Please refer to the
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<ref id="kernelconfig" name="Configuring the FreeBSD Kernel">
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section for more information on kernel configuration.
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<sect1><heading>Check the tun device</heading>
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<p>My experiences with ppp have only been with one ``tun'' device (tun0). If
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you have used more (i.e., a number other than `1' in the pseudo-device line
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in the kernel configuration file) then alter all references to ``tun0''
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below to reflect whichever device number you are using.
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The easiest way to make sure that the tun0 device is configured correctly is
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to re-make it. To this end, execute the following commands:
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<tscreen><verb>
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# cd /dev
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# ./MAKEDEV tun0
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</verb></tscreen>
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<sect1><heading>PPP Configuration</heading>
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<p>The meat of the problem.
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Confusingly, it appears that both user ppp and pppd (the kernel level
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implementation of PPP) both assume configuration files kept in
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/etc/ppp. However, the sample configuration files provided are good for
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user ppp, so keep them around for reference. The easiest way to do this is:
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<tscreen><verb>
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# cd /etc
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# mv ppp ppp.orig
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# mkdir ppp
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</verb></tscreen>
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Configuring ppp requires that you edit somewhere between one and three
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files, depending on your requirements. What you put in them depends to some
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extent on whether your ISP allocates IP addresses statically (i.e., you get
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given one IP address, and always use that one) or dynamically (i.e., your IP
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address can be different during different PPP sessions).
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However, there are a few things that you should do first, regardless of
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whether you are using static or dynamic IP addresses.
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<sect2><heading>Configure the resolver(5)</heading>
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<p>The resolver is the part of the networking system that turns IP addresses
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into hostnames. It can be configured to look for maps that describe IP to
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hostname mappings in one of two places.
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The first is a file called <tt>/etc/hosts</tt> (<tt>man 5 hosts</tt>).
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The second is the Internet Domain Name Service, a distributed
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data base, the discussion of which is beyond the realm of this document.
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The resolver is a set of system calls that do the mappings,
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and you have to tell them where to get their information
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from. You do this by editing the file <tt>/etc/host.conf</tt>. Do
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<bf>not</bf> call this file <tt>/etc/hosts.conf</tt> (note the extra
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``s'') as the results can be confusing.
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This file should contain the following two lines,
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<tscreen><verb>
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hosts
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bind
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</verb></tscreen>
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which instruct the resolver to look in the file <tt>/etc/hosts</tt> first,
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and then to consult the DNS if the name was not found in the
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<tt>/etc/hosts</tt> file.
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It is probably a good idea to make sure you are not running the ``named''
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service. Check your <tt>/etc/sysconfig</tt> file for the line that refers
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to ``namedflags'', and make sure the line reads
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<tscreen><verb>
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namedflags="NO"
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</verb></tscreen>
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<sect2><heading>Create the /etc/hosts(5) file</heading>
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<p>This file should contain the IP addresses and names of machines on your
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network. At a bare minimum it should contain entries for the machine
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which will be running ppp. Assuming that your machine is called
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foo.bar.com with the IP address 10.0.0.1, <tt>/etc/hosts</tt> should
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contain:
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<tscreen><verb>
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127.0.0.1 localhost
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10.0.0.1 foo.bar.com foo
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</verb></tscreen>
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The first line defines the alias ``localhost'' as a synonym for the
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current machine. Regardless of your own IP address, the IP address for
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this line should always be 127.0.0.1. The second line maps the name
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``foo.bar.com'' (and the shorthand ``foo'') to the IP address 10.0.0.1.
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If your provider allocates you a static IP address then use this in place
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of 10.0.0.1.
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<!-- XXX <em>(* What should they do if they are
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allocated an IP address dynamically?)</em> -->
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<sect2><heading>Create the /etc/resolv.conf file</heading>
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<p><tt>/etc/resolv.conf</tt> contains some extra information required when
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you are not running a nameserver. It points the resolver routines at real
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nameservers, and specifies some other information.
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At the very least, <tt>/etc/resolv.conf</tt> should contain one line with
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a nameserver which can be queried. You should enter this as an IP
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address. My <tt>/etc/resolv.conf</tt> contains:
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<tscreen><verb>
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nameserver 158.152.1.193
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nameserver 158.152.1.65
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</verb></tscreen>
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Which are Demon Internet's two nameservers. Add as many ``nameserver''
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lines as your ISP provides nameservers.
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<sect1><heading>PPP and static IP addresses</heading>
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<p>Probably the easiest to configure for. You will need to create three files
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in the <tt>/etc/ppp</tt> directory.
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The first of these is <tt>ppp.conf</tt>. It should look similar to the
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example below. Note that lines that end in a ``:'' start in column 1, all
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other lines should be indented as shown.
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<tt>/etc/ppp/ppp.conf</tt>
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<tscreen><verb>
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1 default:
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2 set device /dev/cuaa0
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3 set speed 9600
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4 disable lqr
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5 deny lqr
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6 set dial "ABORT BUSY ABORT NO\\sCARRIER TIMEOUT 5 \"\" ATE1Q0 OK-AT-OK
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\\dATDT\\T TIMEOUT 40 CONNECT"
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7 provider:
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8 set phone 01234567890
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9 set login "TIMEOUT 10 gin:-BREAK-gin: foo word: bar col: ppp"
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10 set timeout 120
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11 set ifaddr x.x.x.x y.y.y.y
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</verb></tscreen>
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Do not include the line numbers, they are just for this discussion.
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<descrip>
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<tag/Line 1:/ Identifies the default entry. Commands in this entry are
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executed automatically when ppp is run.
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<tag/Line 2:/ Identifies the device that has the modem hanging from it.
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COM1: is <tt>/dev/cuaa0</tt> and COM2: is <tt>/dev/cuaa1</tt>.
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<tag/Line 3:/ Sets the speed you want to connect at.
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<tag/* Lines 4 and 5:/ Do not know exactly what effect these lines have
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<tag/Line 6:/ Dial string commands. user ppp uses the <tt>chat(8)</tt>
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language. Check the manual page for information on the features
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of this language.
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<tag/Line 7:/ Identifies an entry for a provider called ``provider''.
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<tag/Line 8:/ Sets the phone number for this provider. Do not include any
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spaces in the phone number.
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<tag/Line 9:/ Sets the login string sequence. In this example, the string is
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for a service who's login session looks like
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<tscreen><verb>
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J. Random Provider
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login: foo
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password: bar
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protocol: ppp
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</verb></tscreen>
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You will need to alter this script to suit your own needs. It is
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written in the <tt>chat(8)</tt> language.
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<tag/Line 10:/ Sets the default timeout (in seconds) for the connection. So
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the connection will be closed automatically after 120 seconds
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of inactivity.
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<tag/Line 11:/ Sets the interface addresses. The string x.x.x.x should be
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replaced by the IP address that your provider allocates you. The
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string y.y.y.y should be replaced by the IP address that your
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ISP indicated for their gateway.
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</descrip>
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Now you have to edit the file <tt>/etc/ppp/ppp.linkup</tt>:
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<tscreen><verb>
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x.x.x.x:
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add 0 0 HISADDR
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</verb></tscreen>
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Replace x.x.x.x with your IP address as before. This file is used to
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automatically add a default route from your ISP (who's address is
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automatically inserted with the HISADDR macro) to you.
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Finally, you can create the file <tt>/etc/ppp/ppp.secret</tt>, which sets
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some passwords to prevent people messing around with ppp on your system.
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You may or may not want to do this, depending on how many people have
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access to your ppp system.
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<sect1><heading>PPP and Dynamic IP configuration</heading>
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<!-- XXX -->
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<p>If you service provider does not assign static IP numbers,
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<tt>ppp</tt> can be configured to negotiate the local address. This is
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done by specifying 0 as the local IP address:
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<tscreen><verb>
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set ifaddr 0 0
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</verb></tscreen>
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See the <tt>ppp(8)</tt> manual page for more detailed information.
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<sect1><heading>Final system configuration</heading>
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<p>You now have PPP configured, but there are a few more things to do before
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it is ready to work. They all involve editing the <tt>/etc/sysconfig</tt>
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file.
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Working from the top down in this file, make sure the ``hostname='' line
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is set, e.g.,
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<tscreen><verb>
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hostname=foo.bar.com
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</verb></tscreen>
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Look for the network_interfaces variable, and make sure the tun0 device is
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added to the list. My line looks like
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<tscreen><verb>
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network_interfaces="lo0 tun0 ep0"
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</verb></tscreen>
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but I have an ethernet card (ep0) to configure as well.
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Now add an ifconfig line for the tun0 device. It should look something
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like
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<tscreen><verb>
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ifconfig_tun0="inet foo.bar.com y.y.y.y netmask 0xffffffff"
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</verb></tscreen>
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as before, change ``foo.bar.com'' to be your hostname, y.y.y.y is the IP
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address of your providers gateway, and 0xffffffff is the netmask they
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provided you with (in hexadecimal). Two common values for the netmask are
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<tscreen><verb>
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255.255.255.255 = 0xffffffff
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255.255.255.0 = 0xffffff00
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</verb></tscreen>
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Set the routed flags to ``-s'' with the line
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<tscreen><verb>
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routedflags=-s
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</verb></tscreen>
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It is probably worth your while ensuring that the ``sendmail_flags'' line
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does not include the ``-q'' option, otherwise sendmail will attempt to do
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a network lookup every now and then, possibly causing your machine to dial
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out. My sendmail line looks like
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<tscreen><verb>
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sendmail_flags="-bd"
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</verb></tscreen>
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The upshot of this is that I must force sendmail to re-examine the
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mailqueue whenever I have the PPP link up, by typing
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<tscreen><verb>
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# /usr/sbin/sendmail -q
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</verb></tscreen>
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That should be about all you need to do to get PPP working with a static
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IP address. All that is left is to reboot the machine. During startup the
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tun0 device should be detected, and two lines like the following should be
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printed,
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<tscreen><verb>
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tun0: flags=51<UP,POINTOPOINT,RUNNING> mtu 1500
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inet x.x.x.x --> y.y.y.y netmask 0xffffffff
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</verb></tscreen>
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At this point, it should all be working. You can now either type
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<tscreen><verb>
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# ppp
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</verb></tscreen>
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and then ``dial provider'' to start the PPP session, or, if you want ppp
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to establish sessions automatically when there is outbound traffic, type
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<tscreen><verb>
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# ppp -auto provider
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</verb></tscreen>
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This line could be added to your <tt>/etc/rc.local</tt> file.
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