View source for PPP configuration on linux host

DOSBox supports modem connection using tcp sockets. In this page, we describe a simple networking ppp configuration on linux (ubuntu) host. With socat or similar tools on host's side, you can connect these sockets with pppd, and the DOSBox guest can access internet as well.

== WARNING! ==

The included scripts and manuals are dangerous! It needs sudo or root access to the target host, uses external dependencies, can cause damage and irrecoverable package dependency problems via apt installing, and may be harmful when you are not familiar with tcp/ip ipv4 networking or linux iptables/pppd/etc. tools.

== Prerequisities under ubuntu ==

=== Internet settings ===

A working internet connection is essential.
192.168.7.0/30 network must be unused! Otherwise network range collision will happen, causing unpredictable results!
In this example, it leaves garbage in iptables after exiting, so a reboot or an iptables chain purging may be necessary!
Make sure that no telnet service is running on the system, and also no other application uses the TCP 23 port! Otherwise the following steps or scripts will cause damage!

=== Required ubuntu packages ===

And also the following packages need to be installed (may need some other ppp stuff, depending on linux flavour):

 apt-get install bash dosbox iptables p7zip-full ppp sudo wget

== Launch a networked session under ubuntu ==

=== Creating working directory ===

Open a terminal, then create a standalone folder and then enter it, e.g.

 mkdir ~/dosppp
 cd ~/dosppp

=== Getting lynx-bobcat application ===

 wget -nc http://www.fdisk.com/doslynx/bobcats/bcat-e07.exe

=== Extract bobcat ===

md5sum: 8ec09c609b4a2148d249f77e22e670b1

 7z x bcat-e07.exe

=== Creating files ===

The following filenames are case sensitive! Save these 5 files as textfiles to the actual directory ( ~/dosppp in our example )!

==== Create runme.sh ====

 #!/bin/bash
 #
 # by Peter Naszvadi, 2012-2016
 #
 Uid="$(find "$0" -printf '%U' -quit)"
 sudo -u "#$Uid" wget -nc http://www.fdisk.com/doslynx/bobcats/bcat-e07.exe
 sudo -u "#$Uid" bash ./setup.sh
 sudo -u "#$Uid" nohup dosbox -conf dosppp.cnf &
 Pid="$!"
 Serial="/dev/serial$$"
 grep -q 1 /proc/sys/net/ipv4/ip_forward || \
     ( echo 1 1>/proc/sys/net/ipv4/ip_forward )
 iptables -L -t nat | grep '^MASQ.*192\.168\.7\.0/30' || \
     iptables -t nat -A POSTROUTING -s 192.168.7.0/30 -j MASQUERADE
 while ps $Pid >/dev/null
 do
     if sleep 0.1 && pgrep socat
     then
         echo Socat is already running...
     else
         socat TCP4-LISTEN:23 PTY,link="${Serial}" &
         Pid2="$!"
     fi
     sleep 0.5
     if pgrep pppd
     then
         echo pppd is running...
         sleep 1
     else
         pppd "${Serial##*/}" defaultroute mtu 576 192.168.7.1:192.168.7.2
     fi
 done
 echo dosbox exited
 kill -9 "$Pid2"
 pkill -9 pppd
 [ -e "$Serial" ] && rm "$Serial"
 exit 0

Set attributes of runme.sh:

 chmod 755 runme.sh

==== Create BCATDIAL.BAT ====

 @echo off
 NETDIAL BASE 0x3F8 IRQ 4 9600
 epppd base 0x3F8 irq 4 pktvec 0x60 9600 asyncmap 0 crtscts 
 call IP-UP.bat
 set MYIP=192.168.7.2
 echo my_ip=%MYIP% > path.cfg
 set remip=192.168.7.1
 echo gateway=%remip% >> path.cfg
 set netmask=255.255.255.252
 echo netmask=%netmask% >> path.cfg
 set nameserver=8.8.8.8
 echo nameserver=8.8.8.8 >> path.cfg
 cd .\bobcat
 if exist history.htm del history.htm >nul
 lynx -show_cursor -cache=5
 cd ..
 termin 0x60 
 netdial BASE 0x60 IRQ 4 hangup

==== Create dosppp.cnf ====

 [dosbox]
 memsize=32
 [serial]
 serial1=modem listenport:2323
 [autoexec]
 mount c .
 c:
 bcatdial.bat

==== Create NETDIAL.SCR ====

 send "ATZ\r"
 recv 15000 "OK"
 send "ATDTlocalhost\r"
 recv 60000 "~"

==== Create setup.sh ====

 #!/bin/sh
 set -eu
 test -e NEWUSER.BAT || 7z x bcat-e07.exe
 test -e  NETDIAL.EXE || cp ./CONFIG/NETDIAL.EXE ./NETDIAL.EXE
 test -e  EPPPD.EXE || cp ./CONFIG/EPPPD.EXE ./EPPPD.EXE
 test -e  HOLDIT.EXE || cp ./CONFIG/HOLDIT.EXE ./HOLDIT.EXE
 test -e  SETSCRN.COM || cp ./CONFIG/SETSCRN.COM ./SETSCRN.COM
 test -e  TERMIN.COM || cp ./CONFIG/TERMIN.COM ./TERMIN.COM
 test -e  ./BOBCAT/LYNX.CFG || cp ./CONFIG/LYNX.CFG ./BOBCAT/LYNX.CFG
 test -e  ./BOBCAT/WATTCP.CFG || cp ./CONFIG/WATTCP.STD ./BOBCAT/WATTCP.CFG
 test -e  ./BOBCAT/LYNXRC || cp ./CONFIG/LYNXRC ./BOBCAT/LYNXRC
 test -e  ./BOBCAT/HOTLIST.HTM || cp ./CONFIG/HOTLIST.HTM ./BOBCAT/HOTLIST.HTM
 test -e  ./BOBCAT/FTP.HTM || cp ./CONFIG/FTP.HTM ./BOBCAT/FTP.HTM
 test -e  ./BOBCAT/GOPHER.HTM || cp ./CONFIG/GOPHER.HTM ./BOBCAT/GOPHER.HTM
 test -e  ./BOBCAT/WWW.HTM || cp ./CONFIG/WWW.HTM ./BOBCAT/WWW.HTM
 test -e  ./BOBCAT/TELNET.HTM || cp ./CONFIG/TELNET.HTM ./BOBCAT/TELNET.HTM
 test -e  ./BOBCAT/IRC.HTM || cp ./CONFIG/IRC.HTM ./BOBCAT/IRC.HTM
 test -e  ./BOBCAT/FORMS.HTM || cp ./CONFIG/FORMS.HTM ./BOBCAT/FORMS.HTM
 test -e  ./MINITEL/WATTCP.CFG || cp ./CONFIG/WATTCP.STD ./MINITEL/WATTCP.CFG
 test -e  ./FTP/WATTCP.CFG || cp ./CONFIG/WATTCP.STD ./FTP/WATTCP.CFG
 test -e  ./BOBCAT/EXTERNAL/FTP.BAT || cp ./CONFIG/FTP.TAB ./BOBCAT/EXTERNAL/FTP.BAT
 test -e  ./BOBCAT/EXTERNAL/HTTP.BAT || cp ./CONFIG/HTTP.TAB ./BOBCAT/EXTERNAL/HTTP.BAT
 test -e  ./BOBCAT/EXTERNAL/GOPHER.BAT || cp ./CONFIG/GOPHER.TAB ./BOBCAT/EXTERNAL/GOPHER.BAT
 test -e  ./BOBCAT/EXTERNAL/TELNET.BAT || cp ./CONFIG/TELNET.TAB ./BOBCAT/EXTERNAL/TELNET.BAT
 test -e  ./BOBCAT/EXTERNAL/IRC.BAT || cp ./CONFIG/IRC.TAB ./BOBCAT/EXTERNAL/IRC.BAT
 test -e  SCRIPIT.DEF || cp ../DOCS/SCRIPIT.DEF ODSCRIPIT.DEF
 test -e  NETDIAL.STD || cp ../DOCS/NETDIAL.STD NETDIAL.STD

=== Launch runme.sh ===

 sudo ./runme.sh

If everything is okay, you can get similar result like this:

[[File:dosbox_epppd_lynx.gif]]

=== Links ===

Visit for more information:
http://www.vogons.org/viewtopic.php?t=27920