This is a DRAFT release of the NET-2-FAQ. Please MAIL comments, my USENET
access has been flaky at best. :)

I was planning to put off posting this until I received feedback from the
NET folks, but I'm afraid it can't wait. Even if this is incomplete, it
has to help somebody. :) 

PLEASE---this is a draft release. I need to get feedback from other folks on 
their own experiences installing NET-2; i.e. what things they did differently 
from the instructions here, any gotchas or caveats that I forgot to mention, 
any other hints, etc. At the very least, if you read this doc, please send me 
a rating from 1 to 10 on how useful you think it is. 

As soon as I have some feedback I will post an official version with 
updates... hopefully in 2 or 3 days. Look for it in comp.os.linux.announce, 
the NET channel, on the various Linux FTP sites... and, soon to be a major 
motion picture! (``Jurassic Kernel'', of course.)

Please send any comments or suggestions ASAP. Thanks!

mdw

--
This is the Linux NET-2-FAQ v0.1, 26 June 1993
By Matt Welsh <mdw@tc.cornell.edu> and Terry Dawson <terryd@extro.ucc.su.oz.au>

"Real Programmers don't write documentation." --Ancient Proverb

0. Introduction
        This is the NET-2-FAQ, which is a rewrite of the earlier NET-FAQ for
        the new NET-2 TCP/IP code in Linux kernels 0.99.pl10 and above. 

        The NET-2 code is the new kernel-based networking support for Linux,
        written by Fred van Kempen <waltje@uwalt.nl.mugnet.org>. It is based 
        on the NET-1 code by Ross Biro <bir7@leland.stanford.edu>, device 
        drivers by Donald Becker <becker@super.org>, and SLIP drivers by 
        Laurence Culhane <loz@holmes.demon.co.uk>. Many others too numerous
        to mention have provided support, bug fixes, and help. 

        This NET-2-FAQ is by Matt Welsh and Terry Dawson. It covers setup and
        configuration of TCP/IP under Linux using NET-2. It also hopefully 
        answers some of the many questions about the NET-2 code and common
        problems that people have. It does not cover using TCP/IP (i.e.
        using telnet, FTP, etc.) I'd like to keep this document as short as
        possible... :)

        DISCLAIMER: The NET-2 code is currently under development, which means
        that it may not be as stable and easy to configure as you may like it
        to be. The code is relatively new and bug fixes are being posted every
        day, so if you run into a large number of problems just hang in there.
        The software has stabilized greatly over the last few weeks (evidenced
        by the fact that it's included in Linus' standard kernel). 

        If you have questions about the NET-2 code, please READ this NET-2-FAQ
        first and then join the NET channel of the Linux-activists mailing list
        by sending mail to
                linux-activists-request@niksula.hut.fi
        with the line
                X-Mn-Admin: join NET
        at the top of the message body (not the subject). Note that the SLIP
        channel of the mailing list has been disabled and the NET channel 
        should be used for SLIP discussions as well. Furthermore keep in mind
        that the NET channel is for development discussions only. If you have
        general configuration questions you can mail the authors of this FAQ
        (mdw@tc.cornell.edu and terryd@extro.ucc.su.oz.au) or post to the
        newsgroup comp.os.linux. Please do NOT bug the NET-2 developers 
        directly unless you have a development-related issue (especially Fred: 
        he has to pay $$$ for his e-mail access). :)

        There is a forthcoming book from the Linux Documentation Project 
        entitled ``Linux Network Administration Guide'' by Olaf Kirch. It 
        covers all aspects of setting up and using networking under Linux, 
        including TCP/IP, UUCP, mail, news, etc. Once this book is officially
        released, it should suppliment the NET-2-FAQ and cover all of the
        other aspects of using TCP/IP. This guide simply covers setup of 
        NET-2, i.e., "How to put your machine on the net."

        New versions of this NET-2-FAQ and be retrieved via anonymous
        FTP from sunsite.unc.edu:/pub/Linux/docs or directly from me
        (mdw@tc.cornell.edu). It will also be posted to the newsgroups 
        comp.os.linux.announce, comp.os.linux, and news.answers. 


1. NET-2 Supported Functionality
        The NET-2 code is a complete kernel implementation of TCP/IP for
        Linux, including many features not found in the original networking
        code. NET-2 supports many popular Ethernet cards, real IP routing,
        and SLIP (Serial Line IP) for TCP/IP connections over the phone line
        via modem. 

1.1 Supported Ethernet cards
        NET-2 supports the following Ethernet cards:

        3com 3c503, 3c503/16
        Novell NE1000, NE2000
        Western Digital WD8003, WD8013
        Hewlett Packard HP27245, HP27247, HP27250 (these drivers could
          do with more testing)

        The following clones are reported to work:
        WD-80x3 clones: LANNET LEC-45
        NE2000 clones: Alta Combo, Artisoft LANtastic AE-2, Asante Etherpak
          2001/2003, D-Link Ethernet II, LTC E-NET/16 P/N 8300-200-002,
          Network Solutions HE-203, SVEC 4 Dimension Ethernet, 4-Dimension
          FD0490 EtherBoard 16.


        As mentioned above NET-2 also supports SLIP in the kernel. Therefore
        if you don't have an Ethernet connection you can do TCP/IP over the
        phone line, provided you have a SLIP server nearby (many universities
        and businesses provide SLIP access to employees/students) and a
        compatible modem (usually 14.4 v.42bis, depending on your SLIP server).
        I recommend the Infotel 144DF Internel v.32bis modem (about US$189) for
        most SLIP servers.


2. Getting the NET-2 Software
        Before you can configure TCP/IP on your system you need to get the
        appropriate software. This includes the current version of the Linux
        kernel (0.99.pl10 or above), TCP/IP configuration programs and files
        (e.g., /etc/ifconfig, /etc/hosts), and finally a set of network
        application programs (such as telnet, ftp, rlogin, etc.). 

        The current kernel version is found in
        nic.funet.fi:/pub/os/linux/PEOPLE/Linus/linux-0.99.10.tar.z.

        The current libraries (libc-4.4.1), found in 
        sunsite.unc.edu:/pub/Linux/GCC/image-4.4.tar.z. (You'll probably want 
        to install the include files in inc-4.4.tar.z as well! See the 
        READMEs there for details.)

        The current NET-2 configuration file distribution is in
        tsx-11.mit.edu:/pub/linux/packages/net/sources/net/net-010.tar.z.

        The TCP/IP application binaries and setup files are found in
        tsx-11.mit.edu:/pub/linux/packages/net/net-2. Get the three
        files in this directory: net-base.tar.z, net-std.tar.z, and
        net-ext.tar.z.

2.1 Unpacking the software
        First, unpack the kernel sources in /usr/src. This will put all
        of the kernel sources under /usr/src/linux (the usual place).
                # cd /usr/src
                # zcat linux-0.99.10.tar.z | tar xvf -

        Next, unpack the libraries. 
                # cd /
                # zcat image-4.4.tar.z | tar xvf -
        Now, make the links to the new libraries in /lib. BE VERY CAREFUL
        that you do not delete the previous links. Do everything in
        one step, as so:
                # ln -sf /lib/libc.so.4.4 /lib/libc.so.4
                # ln -sf /lib/libm.so.4.4 /lib/libm.so.4

        Next, unpack the net-base package, which contains the basic
        utils and configuration files in /etc. Note that net-base makes
        symlinks in /etc for all of your TCP/IP configuration files to /conf.
        For example, /etc/hosts is a symlink to /conf/net/hosts. Why is this
        done? Because Fred's Linux/PRO distribution of Linux keeps all
        machine-specific configuration files in /conf. And because this is
        the way he does it, we may as well too. In general it makes things
        easier to locate. If you want to keep all of your net files in 
        /etc, that's fine, but you'll have to put them there by hand.

        You may wish to make a backup of everything in /etc before you unpack
        net-base. Just unpack it from / (the root directory):
                # cd /
                # zcat net-base.tar.z | tar xvvofp -

        Also, unpack net-std.tar.z, which contains the network clients and
        damons (e.g., telnet and telnetd). Unpack it from / as well:
                # cd /
                # zcat net-std.tar.z | tar xvvofp -


        If you wish to use tin (a newsreader), unpack the net-ext package
        from /:
                # cd /
                # zcat net-ext.tar.z | tar xvvofp -


        Finally, unpack the net-010 package, which contains the sources
        for the TCP/IP setup programs (ifconfig, arp, route, etc.) and the
        configuration files in /conf/net. This is unpacked into 
        /usr/src/net-010.
                # mkdir /usr/src/net-010
                # cd /usr/src/net-010
                # zcat net-010.tar.z | tar xvvofp -

2.2 Putting things in the right place
        Everything is now in the right place, but the configuration files
        in /conf/net aren't there (only the symlinks to them in /etc). 
        The easiest way to get them is to copy them from the net-010
        distribution:
                # mkdir -p /conf/net
                # chown -R root.root /conf; chmod -R 755 /conf
                # cp /usr/src/net-010/etc/* /conf/net

        You should make sure that all of the symlinks to /conf/net in /etc
        can be resolved (that is, try to "more" or "cat" each file, make
        sure you don't get any errors). Also note that some files will
        be duplicated: for example, /etc/inetd.conf is a symlink to 
        /usr/etc/inetd.conf. However, from the cp command above you also
        have a /conf/net/inetd.conf, which can be deleted (remember that
        all of the programs still look in /etc, not /conf. So whatever is
        in /etc is the file which is actually being used).

        (Note: Fred tells me that in the next net-011 distribution the files
        in /conf are in the right place. But just in case I'll leave the
        information above. :) --mdw)

3. Building the Kernel
        You're now ready to build the new 0.99.pl10 kernel with the NET-2
        code enabled. 

3.1 Configuring the NET-2 kernel code
        First, you need to read and modify the file
                /usr/src/linux/net/inet/CONFIG
        which specifies the drivers used by the NET-2 code in the kernel.
        Also see the various README files in /usr/src/linux/net/inet which
        explain the format of these files.

        One important line is the "CARDS=" definition, where you define
        the drivers to compile into the kernel. For example, if you're
        using the WD8003/WD8013 driver and the 3c503 driver, you'd set
        the CARDS line to
                CARDS = -DWD80x3 -DEL2
        For SLIP, you'd set it to
                CARDS = -DSLIP

        You also need to set the "OPTS" and "WD_OPTS" lines to the
        appropriate values. WD and SMC cards need to set EI8390 to your
        base address (ex. -DEI8390=0x280) and EI8390_IRQ to your card's
        IRQ (ex. -DEI8390_IRQ=15). One of the most common problems when using
        network cards is an IRQ conflict. The IRQ and base address are
        generally modifyable by jumpers on your card. Make sure that you're
        not using an IRQ used by any other card in your machine.

        Furthermore for WD and SMC cards you need to set WD_SHMEM to the
        shared memory address. This is all very self-explanatory when you
        look at the CONFIG file.

        For all other cards, you can set EI8390 and EI8390_IRQ to 0, which
        tells the driver to autoprobe for the IRQ and base address. If 
        this doesn't seem to work for you try defining them directly.

        See the file CONFIG for a list of the other available options for
        SLIP and other drivers. I don't want to go into too much detail 
        here since this tends to change from release to release. If you have
        questions you can mail me (mdw@tc.cornell.edu).

3.2 Building the kernel
        After the /usr/src/linux/net/inet/CONFIG file is set up correctly,
        you can build the kernel as you normally would (see the file
        /usr/src/linux/README if you've never done this before). Essentially
        this entails editing /usr/src/linux/Makefile to set root device and
        default display mode. (*Note: keyboard is now handled by loadable
        keymaps as of 0.99.pl10; grab the file keytable.tar.z from your 
        nearest Linux ftp site). 

        Next run make config. Make sure you answer "yes" to all three of
        "TCP/IP Networking?", "NFS Support?" and "/proc filesystem support?".

        Finally do 'make dep' and 'make'. You now have a new 0.99.10 kernel 
        with NET-2 set up. I wouldn't reboot it quite yet as we still have
        to configure the NET-2 programs before it will work correctly.

4. Configuring NET-2 TCP/IP
        The final step is to modify the various setup files to get NET-2
        working. After this is ready you can boot your new kernel and 
        go happily netting (if all goes well).

        In this section I'll describe each of the major TCP/IP setup files,
        what they do, and what you need to do to configure them. Remember
        that everything is *really* found in /conf/net but there are symlinks
        in /etc. Therefore when I say "/etc/hosts" I'm also refering to 
        "/conf/net/hosts". They are the same file. 

        If you're using SLIP, see section 5.0 on configuring SLIP. The
        discussion below is for Ethernet connections only. So, SLIP users:
        skip all of part 4.0 and go directly to part 5.0.  

4.1 /etc/rc.d/rc.inet1 and /etc/rc.d/rc.inet2
        For the non-UNIX wizard: "rc" files are run at bootup time by the
        "init" program and start up all of the basic system programs, such
        as sendmail, cron, etc. as well as the NET-2 daemons (such as inetd).
        For NET-2 the rc files are found in /etc/rc.d. It doesn't really
        matter where you keep them, as long as init can find them. (We'll
        go into this later). 

        First things first. The file /etc/rc.d/rc.inet1 configures the basic
        TCP/IP interface to your machine, using two programs: /etc/ifconfig
        and /etc/route. These two programs tell the kernel how to route and
        manage TCP/IP connections to your system, by setting things such as
        the IP address, network mask, and so on.

        Note that in the previous NET-1 code, the "config" program was
        used. However, the "standard" for UNIX system TCP/IP configuration
        is to use ifconfig and route, and this has been implemented with NET-2.

        Below you're going to edit rc.inet1 to use the correct ifconfig and
        route commands for your machine. But first, you need to know the
        following information about your network setup:

        * IP address: this is the unique machine address in dotted-decimal
          format. An example is 128.253.153.54. Your network admins will 
          provide you with this number. If you're only configuring loopback
          mode (i.e. no SLIP, no ethernet card, just TCP/IP connections
          to your own machine---called "loopback") then your IP address is
          127.0.0.1.

        * Your network mask ('netmask'). Again, your network admins will
          supply this. Most networks are class C subnetworks which use
          255.255.255.0 as their netmask. Other Class B networks use
          255.255.0.0. If one of these doesn't work, try the other. If this
          doesn't work, ask your local net guru for help.

        * Your network address. This is your IP address masked with the netmask.
          For example, if your netmask is 255.255.255.0, and your IP address
          is 128.253.154.32, your network number (IP addr AND netmask) is 
          128.253.154.0. With a netmask of 255.255.0.0, this would be 128.253.0.0. 

        * Your gateway address. This is the address of the machine which
          is your "gateway" to the outside world (i.e. machines not on your
          subnet). In general the gateway machine has an IP address identical
          to yours but with a ".1" in the last position; e.g. if your IP
          address is 128.253.154.32, your gateway might be 128.253.154.1.
          Your network admins will provide you with the IP address of your
          gateway.

NET-2 supports full routing, with proxy ARP, multiple routes, subnetworking,
the whole nine yards. The above describes most basic TCP/IP configurations.
Yours may be quite differnent: when in doubt, consult your local network
gurus and check out the man pages for "route" and "ifconfig" included with
the net-010 package. Configuring TCP/IP networks is very much beyond the
scope of this FAQ; the above should be enough to get most people started.

4.1.1 Editing rc.inet1
        Edit the file /conf/net/rc.inet1. This file uses the "ifconfig" and
        "route" commands to configure your network interface at boot time.

        You may need to do some heavy surgery on this file to get it to look
        right; it may be easier to delete it and start from scratch. Given
        the information above, a possible rc.inet1 should look like:

#!/bin/sh
# rc.inet1: configure the network interface

HOSTNAME=`hostname`

# Attach the loopback device. 
/etc/ifconfig lo 127.0.0.1  
/etc/route add 127.0.0.1

# IF YOU HAVE AN ETHERNET CONNECTION, use these lines below to configure the 
# eth0 interface. If you're only using loopback or SLIP, don't include these 
# lines.

# Edit for your setup.
IPADDR="128.253.154.32"  # REPLACE with YOUR IP address!
NETMASK="255.255.255.0"  # REPLACE with YOUR netmask!
NETWORK="128.253.154.0"  # REPLACE with YOUR network address!
GATEWAY="128.253.154.1"  # REPLACE with YOUR gateway address!
/etc/ifconfig eth0 ${IPADDR} netmask ${NETMASK} 
/etc/route add ${IPADDR}
/etc/route add ${NETWORK}
/etc/route add default gw ${GATEWAY} metric 1

# End of rc.inet1


        This is a basic rc.inet1 to run the ifconfig and route commands
        needed to set up a basic TCP/IP connection. Edit this for your setup.
        To ensure that this will be run at boot time, make sure that you
        include the command
                /bin/sh /etc/rc.d/rc.inet1
        in your /etc/rc, or in your /etc/inittab (if you're running the
        sysvinit package).


4.1.2 Editing rc.inet2
        The rc.inet2 script is also run at boot time, AFTER rc.inet1.
        It starts up various TCP/IP daemons such as inetd, portmapper, 
        and so on.

        You will probably want to comment out most of this file, especially
        if you're not planning on using NFS (Network File System). You 
        MUST leave the stanza to run inetd and syslogd uncommented. 

        If you're not going to be using NFS, you can comment out the lines
        to run: rpc.portmap, ugidd, mountd, routed, nfsd, pcnfsd, and bwnfsd.
        Most of these aren't included with NET-2 anyway. You can comment
        out the stanza to run "umail" unless you have that package. In general,
        most of the things found in rc.inet2 are "sole separately". I would
        only start up inetd and syslog at first until you get everything 
        going.

        NOTE: You do NOT need to run named. Named allows your machine to act
        as a name server. Most machines on the net have a nameserver 
        available to them (your network admins can tell you the address). 
        Because named uses some system resources and waste CPU and network
        time if you already have a nameserver, I suggest that you don't run
        named unless you don't have a nameserver or are on a local network 
        that's not connected to the outside world. 

        Therefore In most cases you can safely comment out the stanza to run 
        named in rc.inet2. There's no reason to run it unless you don't
        have a nameserver out on the net. (Which you probably do.)

4.2 /etc/hosts
        /etc/hosts contains a list of IP addresses and the hostnames they 
        map to. In this way, you can refer to other machines on the network
        by name, as well as by IP address. Using a nameserver (see section 4.3)
        also allows you to do the name->IP address translation automatically.

        This file needs to contain at least an entry for "127.0.0.1" with
        the name "loopback". You may also wish to include entries for
        your gateway and network addresses. 

        If you have an Ethernet connection, you need to include an entry
        for your own machine, with your full hostname (if you have one) and
        the alias "localhost". For example, if "loomer.vpizza.com" has the
        IP address "128.253.154.32", my /etc/hosts file would look like:

# /etc/hosts: List of hostnames and IP addresses
127.0.0.1               loopback
128.253.154.32          loomer loomer.vpizza.com localhost

        Once again, edit this for your own needs. 

        The line "%%IP%%        %%HOST%% %%ALIAS%%" can be deleted from 
        this file! This is a "tag" line used by Fred's experimental net
        config scripts. I'm now writing a new set of scripts which don't
        use these lines. In any of these files, you see curious lines with
        entries such as "%%NAME%%", these lines can be deleted.

4.3 /etc/networks
        The file /etc/networks contains known network addresses, much like
        /etc/hosts contains known IP addresses. In general you only need 
        network addresses for loopback and your own local network (your
        network address). For example, my network address is 128.253.154.0,
        thus my /etc/networks looks like:

loopback        127.0.0.0 
localnet        128.253.154.0

        

4.4 /etc/host.conf
        This file specifies how your system will lookup names. 
        It should contain the two lines:
                order hosts,bind
                multi

        These two lines tell the resolve libraries to first check the 
        /etc/hosts file for any names to lookup, and then ask the nameserver
        (if one is present). The "multi" entry allows you to have multiple
        names on one line in the /etc/hosts file, as above in section 4.2.

4.5 /etc/resolv.conf
        This file contains two entries: The address of your nameserver
        (if any), and the name of your domain (if you have one). If you
        are running your own nameserver (i.e., you're running named on your
        own machine), then the nameserver address is your own IP address
        (or 127.0.0.1 for loopback machines). 

        Your domain name is your fully-qualified hostname (if you're a
        registered machine on the Internet, for example), with the hostname
        chopped off. That is, if your full hostname is loomer.vpizza.com,
        your domain name is just "vpizza.com", without the hostname ("loomer").

        For example, if your machine is goober.norelco.com, with a nameserver
        address of 128.253.154.5, your /etc/resolv.conf would be:

                nameserver 127.253.154.5
                domain norelco.com

4.6 /etc/HOSTNAME
        This is a new file; it contains the hostname of your machine (without
        the domain name). For example, the machine above would have the
        file /etc/HOSTNAME:
                goober
        That's all.

4.7 /etc/rc.local
        Change the line in /etc/rc.local (or /etc/rc, depending on your
        setup) which sets your system's hostname, to 
                /bin/hostname -S

        (You have a new hostname in /bin.) This sets your hostname from
        the name found in /etc/HOSTNAME. If you don't like this (personally
        I don't), just do:
                /bin/hostname -S <your-hostname>

        For example,
                /bin/hostname -S loomer

4.8 Other files
        There are of course many other files in /etc which you may need to
        dabble with later on. Instead of going into them here, I'm going to
        provide the bare minimum to get you on the net. More information will
        be provided in later versions of the NET-2-FAQ.

        Once you have all of the files set up, and everything in the 
        right place, you should be able to reboot your new kernel and
        net away to your heart's content. However, I strongly suggest
        that you keep a bootable copy of your old kernel and even possibly
        a "recovery disk" (say, the SLS a1 disk) in case you hosed your
        /etc/rc files, for example, and can't login when you boot. 


5. Configuring SLIP
        SLIP (Serial Line Internet Protocol) allows you to use TCP/IP 
        over the phone line, with a modem (no need for an Ethernet card).
        Of course, to use SLIP you'll need access to a dial-in SLIP server
        in your area. Many universities and businesses provide SLIP access
        all over the world. 

        Configuring SLIP is much like configuring an Ethernet interface
        (please read section 4.0 above). However, there are a few key
        differences. 

        First of all, dialing in and connecting to your SLIP server is 
        usually done at boot time, usually by a program called "dip" 
        (found in the "dip" subdir of the net-010 package). "Dip" not only 
        dials and logs you into the SLIP server, but it also initiates the 
        SLIP connection and runs the appropriate ifconfig and route commands 
        to initialize the device. Therefore, the only lines needed in 
        /etc/rc.d/rc.inet1 are the two commands to initilize the loopback 
        connection at the top (see section 4.1.1 above).

        If you're not using DIP, you may indeed have to edit rc.inet1 for
        your SLIP parameters.

        Also, there are two types of SLIP servers: Dynamic IP address
        servers and static IP address servers. Dynamic servers allocate
        a new, different IP address to you every time you dialin and
        initiate a connection. Static servers give you the same address
        every time. Almost every SLIP server will also prompt you for
        a username and password when dialing in: DIP can handle logging
        you in automatically.

        Essentially, configuring a SLIP connection is just like configuring
        for loopback or ethernet. The main differences are discussed below.
        Read section 4.0 above for information on configuring your TCP/IP
        files, and apply the changes below.

5.1 Static SLIP server connections
        If you have a static-allocation server (same IP address every time),
        then you may want to put entries for your hostname and IP address
        (since you know what your IP address is!) in /etc/hosts. You should
        also configure the other files listed in section 4: rc.inet2, 
        host.conf, resolv.conf, /etc/HOSTNAME, and rc.local). Remember that
        when configuring rc.inet1, you don't need to run the ifconfig and
        route commands other than the two for the loopback interface (if
        you're using DIP to dial your connection).

        In general, your gateway is the IP address of your SLIP server.
        Because DIP handles the configuration of the route, you probably
        don't need to know this, but in some cases you might have to run the
        appropriate ifconfig or route commands in /etc/rc.d/rc.inet1 to
        get it to work correctly. Instead of using "eth0" as your interface 
        name, SLIP connections use "sl0".  Keep in mind that you can't
        ifconfig sl0 until you have dialed the connection and connected to
        the SLIP server.

        Also, you may need to use the "dstaddr" argument to ifconfig for
        some SLIP servers. For example, if your SLIP server's address is
        44.136.8.5, and your IP address is 128.253.154.32, you may need to
        run the command 
                /etc/ifconfig sl0 128.253.154.32 dstaddr 44.136.8.5

        See the man pages for ifconfig in the net-010 package.

5.2 Dynamic SLIP server connections
        If your SLIP server allocates a new IP address to you every time
        you dialin, you don't know your IP address at all, so you can't
        include an entry in /etc/hosts for your machine. (If you want, you 
        can place your hostname in /etc/hosts with the loopback address 
        127.0.0.1). 

        Most dynamic SLIP servers tell you your IP address when you initiate 
        the connection. For example, it may print a string such as, "Your IP 
        address is 128.253.154.10. Server address is 128.253.154.1." DIP will 
        need to know these numbers when it configures the connection. See 
        section 5.3 below on using DIP.

        If you use DIP, it does all of the work of configuring the 
        connection when you dialin, so rc.inet1 only needs the two lines
        to configure the loopback address (see section 4.1.1 above). 
        Also, see section 5.1 above. You need to configure all of
        the files listed in section 4.0. Your gateway address (should you
        need to know it) will be the address of the SLIP server. Also,
        you may need to run ifconfig on sl0 using the SLIP server's address
        as the "dstaddr" argument (see section 5.1 above). However, if you
        use DIP, it should be able to do all of the ifconfig and route 
        commands for you.

        One good way to figure out how to configure SLIP on your machine is
        to find someone else who uses the SLIP server (it can be on a PC,
        Mac, UNIX box, whatever) and find out what numbers they use. 


5.3 Using DIP
        DIP can simplify the process of dialing into the SLIP server, logging
        in, starting the connection, and configuring the sl0 device with
        the appropriate ifconfig and route commands. 

        Essentially, to use DIP you'll write a "chat script" which is 
        basically a list of commands to send to DIP along with commands for
        logging in, starting the connection, and so on. See "sample.dip"
        in the net-010 package for an explanation. DIP is quite a powerful
        program, with many options. Instead of going into all of them here
        you should look at the READMEs and the sample files from tsx-11 and
        the net-010 distribution.

        You may notice that the sample.dip script assumes that you're using
        a static SLIP server, so you know what your IP address is beforehand.
        For dynamic SLIP servers, you'll probably need to use the command 
        "dip -t" and use the DIP "local" and "remote" commands by hand after
        the SLIP server prints your IP address. For example,

loomer:~% dip -t
DIP>port cua0      (My modem is on /dev/cua0.)
DIP>speed 57600    (Set the baud rate.)
DIP>reset          (Reset modem and terminal line.)
DIP>send att\r\n   (Send modem init string...)
DIP>dial 2446000   (Dial SLIP server.)
DIP>term           (Enter interactive mode.)

Welcome to Annex Server...
Annex login: mdw1
Annex password: 

User mdw1 authenticated.
Annex> slip       (From SLIP server prompt, give "slip" command to start 
                   SLIP connection.)

SLIP inititated. 
Your IP address is 128.254.254.10, server address is 128.254.254.1.

^] (Hit DIP break key to get back to DIP prompt.)
DIP> local 128.254.254.10  (Give local command to specify my IP address.)
DIP> remote 128.254.254.1  (Specify server's IP address.)
DIP> mtu 1500              (Set SLIP operating parameters... you may not need
                           to do this.)
DIP> mode SLIP             (Start the SLIP mode from DIP.)

loomer:~%

        Now we're running in SLIP mode, and everything should work. The command
                # /etc/ifconfig sl0
        will tell you the current interface parameters; you may need to set 
        some of these by hand if DIP didn't get the correctly. Also, some have 
        found that they need to use the route command to change their operating
        parameters. DIP sets a route for the address of your SLIP server, but 
        you may need to delete this route and add it as your gateway instead. 
        For example, with a SLIP server address of 128.253.154.1, use the 
        commands:
                # /etc/route del 128.253.154.1
                # /etc/route add default gw 128.253.154.1 

        It should be simple to modify the code for DIP in the file attach.c
        to run the route and ifconfig commands that work for you automatically.

        Of course, typing all of those DIP commands may be time consuming. It 
        may be possible to write a DIP chat script to run all of the commands 
        up through dialing the connection and logging in, and then "exit" the 
        script to let you type the "local" and "remote" commands by hand.

        Furthermore, there are patches for DIP by Paul Mossip 
        (mossip@vizlab.rutgers.edu) which modify the "get" command to grab
        the IP address of your host and the server from the output of 
        the SLIP server. This should allow you to do all of the dialing and
        configuration within a chat script just as you would with static
        SLIP servers. 

        You'll have to play with various values for your routes and gateways 
        to get everything going correctly. If you have any information on how 
        you configured your SLIP interface, please drop me a note 
        (mdw@tc.cornell.edu). Include info on your SLIP address, server address,
        gateway, and so on, and what commands you used to set up SLIP. There 
        are various possible configurations for SLIP servers and I'd like to 
        update this NET-2-FAQ with as many hints as possible. :)

6. Are You Stuck?
        Really? Then you should read the man pages for ifconfig and route, 
        included in the net-010 package, and understand their functions. These 
        commands have a lot of flexibility, and because everyone's network 
        setup is different, you may find a way to use ifconfig and route to
        get your connection working. If you do, feel free to send me some mail
        so I can include it in the next update of the NET-2-FAQ. Because of
        my limited amount of experimental data, most of the discussion above
        is about my own setup, and I'd like to generalize it as much as 
        possible.

        I'm currently writing a set of scripts to simplify NET-2 configuration.
        You can pick up the pre-alpha release from tc.cornell.edu, in the file
        /pub/mdw/netconf-0.3.tar.z. These scripts maintain a small database of
        network configuration info, and allow you to easily modify and 
        configure your network interface. The scripts are far from complete:
        I've been waiting until the NET-2 interface itself stabilizes a bit
        more before upgrading it further. 

        Another good place to look for help on setting up NET-2 is the 
        O'Reilly and Associated book ``TCP/IP Network Administration''...
        the one with the crab on the cover. Keep in mind that NET-2 is now
        a "standard" implementation of TCP/IP---this means that ifconfig
        and route work the same under Linux as they do on other UNIX systems.

        Also keep in mind that NET-2 _is_ developing very rapidly---it's
        one of the newest additions to the Linux kernel. Thus, all of the
        bugs haven't been worked out yet, so there may be some problems.
        However, a good rule of thumb is that if you were able to get TCP/IP
        working under kernels before 0.99.pl10, you should be able to get it
        working under NET-2 as well. There are still some issues dealing with
        performance to be fixed, but overall the system works. And, as with
        everything in Linux development, time will cure what ails NET-2. 
        If it's absolutely unusable to you, go back to an earlier kernel 
        version, and wait until things develop further. The code is still
        very new.

7. Miscellaneous
        I'm sure that I've missed something. This NET-2-FAQ was thrown 
        together with the help of Terry Dawson and Jeff Uphoff. I know that
        it is not complete. I am releasing this version of the NET-2-FAQ
        in hopes that it will help some people, and that those who are
        missing important information will get in touch with me, and tell
        me where I'm wrong. :) If you have questions about setting up 
        NET-2, feel free to mail me, or if you have any corrections, additions,
        or errata for this NET-2-FAQ, send me any and all changes (cdiffs
        are nice, but I'm flexible). 

        Of course, thanks to Fred, Linus, Ross, Phil, Paul, Don, and everyone 
        else who helped to develop the NET-2 code and work on previous 
        versions of TCP/IP for Linux and the NET-FAQ. (Sorry, Phil, I lost your
        phone number.) Finally, Linux has a complete implementation of 
        TCP/IP. It may not be for everyone yet. But for those who want to
        do some hacking---here it is! 

        PLEASE send me any comments or questions about the NET-2-FAQ. The 
        sooner I get feedback, the sooner I can release a new version. Thanks.

        Matt Welsh, mdw@tc.cornell.edu
-- 
Matt Welsh, mdw@tc.cornell.edu
Radioactive decay ain't what it used to be.