RUNNING NETSCAPE, TELNET, FTP, LYNX

Last edit: April 12, 1997
           [New ppp, pppkill. Added modem notes.]

To run netscape, a connection to an internet service must be made. The
method applies also to run Telnet, Ftp and Lynx; it depends on kermit
and two shell scripts "ppp" and "pppkill".

Example: Connection to UofU math dept.

        startx          Start X windows
        ppp             "Winsock" ppp connect to UofU annex, 581-8105
        netscape        Industry standard net browser.

The "ppp" can be issued before or after X is started. If ppp and
netscape are not listed in a menu, then launch them from an xterm
window. The same applies to telnet, ftp, lynx (all can run at the same
time).

When netscape, lynx, telnet, ftp are no longer being used, return the phone
line to normal by the command

        pppkill

After this is done, power down the modem.

WARNING: Some kermit versions may make the connection impossible. Send
         email if you get into trouble, gustafso@math.utah.edu.
         See also kermit command "set exit warning off" which appears
         below in kermit script "~/.mykermrc".

=============================TECH NOTES=================================

The mechanics of the shell scripts "ppp" and "pppkill" are as follows.
Interest in this sequence of events is seldom, but needed if the remote
ppp host changes.

For first-time setup, files "/bin/ppp", "/bin/pppkill", "/bin/pppaddress",
"~/.mykermrc", "~/.kermrc-ppp" are created. The first three are executable
shell scripts, made so with "chmod +x /bin/ppp", "chmod +x "/bin/pppkill"
and "chmod +x /bin/pppaddress".

The commands "ppp1" and "ppp2" are defined in kermit's setup file,
/root/.mykermrc. Here's what we are trying to automate:

        pppkill         Kill off last running pppd, if any
        kermit          Start up kermit
        ppp1            Login to annex, issue "ppp" to annex prompt
        ppp2            Redirect pppd /dev/modem 38400 defaultroute
        exit            Exit from kermit, leave pppd running
        pppaddress      Print address of connection (0.0.0.0 on error)

The "redirect" command loads the program pppd into memory with certain
command line arguments. This daemon (pppd) establishes the matching ppp
software that communicates with annex using internet protocol. Picture
the setup as a dumbell, where the bar is the phone line and the bells
are the ppp daemons running on the remote and local hosts.

Kermit itself can be used while pppd is loaded, provided kermit is
started with IP setup, instead of modem line setup. See the kermit
documentation for details on how to do this. A reason to use kermit
instead of telnet is for the customization features of kermit that are
lacking in telnet (color, key maps, etc). This advice applies to 1996
kermits, not older ones. If you have an old one, then upgrade!

                             File /bin/ppp

#! /bin/sh
# File /bin/ppp, used to setup ppp between a
# remote host and the local linux host.
# Kill old ppp connections
pppkill
kermit -C "ppp1,ppp2,exit" >/dev/null &
echo "pppaddress prints the DISPLAY address (all zeros means NONE)."
echo "Making ppp connection on /dev/modem. Listen for dial sounds."

                           File /bin/pppkill

#! /bin/sh
# File /bin/pppkill, used to kill the ppp daemon "pppd"
echo -n "Killing pppd connections."
foo=`ps ax | grep "kermit"`
case "$foo" in
 *kermit\ -C\ ppp1,ppp2,exit*)
    fpid=`echo $foo | cut -d ' ' -f 1`
    kill -9 $fpid
    echo -n " Killed pppd kermit pid=$fpid.";;
esac
foo=`ps ax | grep "pppd"`
case "$foo" in
 *\(pppd\)*)
    fpid=`echo $foo | cut -d ' ' -f 1`
    kill -9 $fpid
    echo -n " Killed inactive pppd pid=$fpid.";;
 *pppd\ /dev/modem*)
    fpid=`echo $foo | cut -d ' ' -f 1`
    kill -9 $fpid
    echo -n " Killed active pppd pid=$fpid.";;
 *)
    echo -n " No active pppd found.";;
esac

                          File /bin/pppaddress

#! /bin/sh
# File /bin/pppaddress
# Echo machine internet address
TMP=`ifconfig ppp0 |grep addr: |cut --delimiter=' ' -f 12 |cut -c 6-`
echo $TMP
echo setenv DISPLAY $TMP:0
echo "export DISPLAY; DISPLAY=$TMP:0"


                          File /root/.mykermrc

set exit warning off
set line /dev/modem
def ppp1 take /root/.kermrc-ppp
def ppp2 redirect pppd /dev/modem crtscts mru 296 mtu 296 defaultroute 38400
echo ppp1 --- PPP connect annex.math.utah.edu, 581-8105
echo ppp2 --- Redirect pppd /dev/modem defaultroute 38400

                         File /root/.kermrc-ppp

# Modem init string is required.
# simple:  output atz\13
# complex: output AT&F1E1Q0V1&C1&D2S0=0+ms=11,,14400,28800\13
# Then:    input 10 OK
# /etc/rc.d/rc.local should contain "setserial /dev/modem spd_vhi"
#  for modern modem of speed 28800bps or greater.
#
set speed 38400
output atdt5818105\13
input 30 CONNECT
input 30 sername
output myusername\13            <== Change this to yours!
input 30 assword
output mypassword\13            <== Change this to yours!
input 30 hangup
input 30 annex
output ppp\13
return

==========================MODEM TECH NOTES==============================

LINUX SERIAL SETUP. All modems, internal or external, require a serial
port setup from command file /etc/rc.d/rc.local (linux only). The usual
command is

                setserial /dev/modem spd_vhi

It causes the serial port to respond with setting 3*38400 = 115200 when
it receives 38400 speed settings. Typical symptoms of errors in the
speed setting are dropping the modem just after startup, dropping
characters and dropping of the modem inside kermit.

Under linux, do not using the numbers 57600, 115200 anywhere within
kermit scripts or setups that try to set the serial port. It's not
handled that way. You have to set the multiplier using "setserial"
in order to get the effect of numbers like 57600 or 115200. Likewise,
don't mix and match, use 38400 everwhere, or 19200 everywhere. It's a
classic mistake to use 14400 or 28800 anywhere on a linux system.

BAUD RATE and BPS. The "baud rate" means 2400 on modern modems, whereas
"bps" means the effective bits per second transmission rate, usually
given as 14400bps, 28800bps or 33.6Kbps. The "bps" setting refers to
compression rates and it is handled by the modem. The baud rate is a
limitation of the phone line and it has nothing much to do with the
modem you bought or the capabilities of your serial port hardware. In
particular, "I have a 28800 baud modem" is a nonsense statement which
probably means "I have a 28800bps modem".

It is true that older serial ports of the 8250 or 16450 variety can give
trouble with newer modems having bps rates of 28800 or higher. See the
linux serial HOWTO for more info on this subject.


FACTORY STRING. It is possible to locate the init string from the DOS
file modem.ini distributed with CISCO systems CONNECT software for
windows 3.x/95. A typical entry looks like this:


  [US Robotics Sportster 28.8 (V.42bis)]
  Init=AT&F1E1Q0V1&C1&D2S0=0
  AnswerInit1=AT&F1E1Q0V1&C1&D2S0=1
  ComBPS=115200
  probe=ATI3
  response=Sportster 28,800/Fax|Sportster 28800/Fax
  FlowControl=Hardware

In unix, only "Init=" and "AnswerInit=" are useful, the second being
used only in case you have set up the unix machine for outside dialup
(an unlikely event for linux).

The string after "Init=" is the string to output in the kermit script.
On some modems it is necessary to limit speed matching negotiations to
the range 14400 - 28800 (elimination of 33.6). This depends on the
remote site. The mechanism for making your own modem obey this request
is to add characters onto the Init string, like this:

                S37=17
or
                +ms=11,,14400,28800

The modem manual generally tells you which syntax will work. The 'S'
and "+ms=" commands are documented in the 'AT' commands.

The 'ATS37=17' command is accepted by most modems, but not all modems
react to this command, even if it is silently accepted. The syntax
'at+ms=' is common to Infotel modems. This syntax sets the 'S' register
automatically, so you shouldn't mix and match the commands. The complete
syntax for testing the effects are as follows:

                ats37?          Query setting of register 37
                at+ms=?         Query possible speed settings
                at+ms=11,,14400,28800   Set speed limits
                ats37=17                Set register content

CUSTOM INIT STRING. In theory,

  output atz\13
  input 10 OK
  output at+ms=11,,14400,28800\13
  input 10 OK

would fix up a modem that has problems hanging on to a connection, or
one that makes strange cycling sounds during connection. The trouble is
that modems use their own syntax for limiting the connect speed, even
though the command may be accepted. You have to read the manual to find
out how it works, or else experiment with the modem, and query what it
does. For example, if you set register 37 with "ATS37=17", then execute
"ATS37?" to see if it worked. A value of "000" means it defaulted and
"19" does nothing. On modems that support the "at+ms=" syntax, use
"at+ms=?" to find out the possible settings.

These problems are unique to 28800/33600 modems. A 14400 or 28800 will
generally work with just "atz"!

========================================================================