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3. Quick Steps to Dialup Networking

These quick steps will enable you to setup dial-up networking on Linux in just five minutes.

You need the following packages:

You can check with rpm -qa | grep -i wvdial for the installed packages on redhat linux. Use equivalent package commands in case of other distributions like Debian or Slackware.

The steps below are for MS Windows NT RAS server. The NT RAS requires noauth in wvdial file. The Linux RAS may need different settings. In the sample example given below, you should replace username john with the user ID given to you to login into remote RAS server.

  1. Edit the file /etc/wvdial.conf and insert lines like
    [Dialer myconnection]
    Username = john
    Password = passwordofjohn
    Phone = 982 1956
    Area Code = 713
    Inherits = Dialer Defaults
    Stupid mode = 1
    

    Change john with whatever.
  2. Edit /etc/ppp/pap-secrets and insert lines like
    # Secrets for authentication using PAP
    # client        server  secret                  IP addresses
    john            ppp0    passwordofjohn
    john            *       passwordofjohn
    

    Change john with whatever.
  3. Edit /etc/ppp/chap-secrets and insert lines like
    # Secrets for authentication using CHAP
    # client        server  secret                  IP addresses
    john            ppp0    passwordofjohn
    john            *       passwordofjohn
    

    Change john with whatever.
  4. Edit /etc/ppp/options and insert lines like
    lock
    defaultroute
    noipdefault
    idle 1200
    usepeerdns
    proxyarp
    

  5. Create a new file /etc/ppp/ip-up and insert lines like
    #!/bin/bash
     
    # This file /etc/ppp/ip-up should not be modified -- make local changes to
    # /etc/ppp/ip-up.local instead
     
    LOGDEVICE=$6
    REALDEVICE=$1
     
    export PATH=/sbin:/usr/sbin:/bin:/usr/bin
     
    [ -f /etc/sysconfig/network-scripts/ifcfg-${LOGDEVICE} ] && /etc/sysconfig/network-scripts/ifup-post ifcfg-${LOGDEVICE}
     
    [ -x /etc/ppp/ip-up.local ] && /etc/ppp/ip-up.local "$@"
     
    exit 0
    

  6. Create a new file /etc/ppp/ip-up.local and insert lines like
    #!/bin/sh
     
    echo "  "
    echo "Before doing route add......"
    echo "Output from netstat -nr is : "
    netstat -nr
    echo "  "
     
    echo " Doing route add now....  "
    # You should change the lines below and add the networks where 
    # your remote machines are ...
    route add -net 156.15.24.0 netmask 255.255.255.0 dev ppp0
    route add -net 172.28.36.0 netmask 255.255.255.0 dev ppp0
    route add -net 172.28.39.0 netmask 255.255.255.0 dev ppp0
    route add -net 172.28.26.0 netmask 255.255.255.0 dev ppp0
     
    echo "After doing route add......"
    echo "Output from netstat -nr is : "
    netstat -nr
     
    echo "  "
    

    When wvdial is started it automatically starts the pppd which automatically calls this script to add route to your remote networks via the PPP link. See 'man pppd'. In the example above I have to connect to remote networks 156.15.24, 172.28.36, 172.28.39 via the PPP link. You should replace these with your settings. You can also manually add or delete the route after starting the PPP.
    bash$ su - root
    bash# route add -net 172.28.26.0 netmask 255.255.255.0 dev ppp0
    bash# route del -net 172.23.2.0 netmask 255.255.255.0 dev ppp0
    

  7. Create a new file /etc/ppp/ip-down and insert lines like
    #!/bin/bash
     
    # This file /etc/ppp/ip-down should not be modified -- make local changes to
    # /etc/ppp/ip-down.local instead
     
    LOGDEVICE=$6
    REALDEVICE=$1
     
    export PATH=/sbin:/usr/sbin:/bin:/usr/bin
     
    [ -x /etc/ppp/ip-down.local ] && /etc/ppp/ip-down.local "$@"
     
    /etc/sysconfig/network-scripts/ifdown-post ifcfg-${LOGDEVICE}
     
    exit 0
    

  8. Create a new file /etc/ppp/ip-down.local and insert lines like
    #!/bin/sh
     
    echo "  "
    echo "Before doing route delete ......"
    echo "Output from netstat -nr is : "
    netstat -nr
    echo "  "
     
    echo " Doing route delete now....  "
    # Lines below should be same as in ip-up.local but with delete
    route del -net 156.15.24.0 netmask 255.255.255.0 dev ppp0
    route del -net 172.28.36.0 netmask 255.255.255.0 dev ppp0
    route del -net 172.23.2.0 netmask 255.255.255.0 dev ppp0
     
    echo "After doing route delete ......"
    echo "Output from netstat -nr is : "
    netstat -nr
     
    echo "  "
    

    When pppd is stopped it automatically calls this script to clean up whatever ip-up script did. See 'man pppd'.
  9. Edit /etc/ppp/peers/wvdial and insert lines like
    noauth user john
    name wvdial
    

    Change john with whatever.
  10. If you have an external modem, then just before dialing, switch off/on the power to modem to reset it.
    bash$ su - root
    bash# tail -f /var/log/messages
    
    Bring up another xterm shell window and 
    bash$ su - root
    bash# man pppd
    bash# man wvdial
    bash# cd /etc/ppp
    bash# nohup wvdial myconnection &
    bash# tail -f nohup.out
    
    Bring up another xterm shell window and 
    bash$ su - root
    bash# ifconfig -a
    And you should see ppp device listed and up and running.
    bash# netstat -nr
    And you should see ppp device listed along with other interfaces.
    

  11. By this step the pppd should have established the routes to remote networks with ip-up.local script. Also pppd should have created the /etc/ppp/resolv.conf for DNS servers. Now, try connect to remote host and verify connections.
    bash$ su - root
    bash# tail -100 /var/log/messages | less
    bash# cat /etc/ppp/resolv.conf
    bash# ifconfig -a
    bash# netstat -nr
    I looked for route to network 156.15.24.0 (You should see your 
    network as per /etc/ppp/ip-up.local)
    bash# ping 156.15.24.68
    bash# telnet 156.15.24.68
    
    You can also edit /etc/hosts and add these hosts
    156.15.24.64    starship
    172.28.36.131   gemstone
    bash# ping starship
    bash# ping gemstone
    bash# telnet gemstone
    bash# ftp gemstone
    

  12. To stop the PPP :
    bash$ su - root
    bash# killall wvdial
    bash# killall pppd
    bash# man killall
    

  13. Now enable non-root user to do dial-up networking with PPP. Make sure that the user belongs to the groups `uucp' and `dialout'.
    bash$ su - root
    bash# su - someuser
    bash$ id
    uid=501(someuser) gid=501(maingid) groups=501(maingid),503(staroffice),505(staff)
    This shows the groups 'someuser' belongs.
    
    bash$ exit
    bash# usermod --help
    bash# usermod -g maingid -G staroffice,staff,uucp,dialout someuser
    bash# chgrp -R uucp /etc/ppp
    bash# chmod -R ug+r /etc/ppp
    bash# chmod -R o-rwx /etc/ppp
    bash# chmod go-rwx /etc/ppp/*secrets
    bash# chmod u+s /usr/sbin/pppd
    bash# su - someuser
    bash$ id
    This will display groups someuser belongs and you should see uucp.
    bash$ nohup wvdial myconnection &
    bash$ tail -f nohup.out
    

    It is very strongly recommended that you use wvdial as `normal' user, and make sure that the user belongs to the groups `uucp' and `dialout'.
  14. See also the frontend tool for wvdial at X-wvdial.
  15. If you do not have any other interface ethernet cards for Cable modem or DSL modem then you can setup telephone dial-up modem as the default route for all outside conections to internet. Assuming you only have modem connection via POTS (Plain Old Telephone System) you can do -
    bash$ su - root
    bash# man route
    bash# ifconfig -a
    And look for the IP address of the ppp device, and use it below
    bash# route add default gw  IP_of_ppp_device
    For example -
    bash# route add default gw  172.28.36.3
    

3.1 Troubleshooting

In case you have problems:


bash$ su - root
bash# tail -f /var/log/messages
And then start myconnection in /etc/wvdial.conf
bash# wvdial myconnection

bash# ifconfig -a
Should list ppp

bash# netstat -nr
Should list ppp

If you have multiple interfaces, like ethernet cards to DSL or Cable modem,
to check which route is being used, do:
bash# traceroute www.yahoo.com
bash# traceroute remotehostname

3.2 Graphical Tools

Preference should be given the console line commands as in previous section, but some people prefer GUI interface. You can use graphical tools like Linuxconf, KPPP, GnomePPP and many others.

Note: I very strongly recommend using command-line console commands 'wvdial' as demonstrated in previous sections, as they are lot simpler and easy to use.


bash$ su - root
bash# linuxconf &
And select Networking->Client Tasks->Routing & Gateways->Set Other Routes to networks->Add network
. Also select Networking->PPP

bash# rp3 &
bash# rp3-config &


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