How To: Configure vpnc

Alex Brandt 2010-01-11 22:43 Comments

Introduction

vpnc is a handy Cisco virtual private network (VPN) client. This allows remote work, secure network connections, &c. Our university uses Cisco VPN services to allow remote access to internal servies (i.e. license servers).

Installing vpnc

vpnc is found in many distributions' package management systems. Before scouring for the sources try searching the package manager. Otherwise, install the source with the following standard build process:

make
su -c "make install"

The other thing to keep in mind is that vpnc requires tun/tap to be built into your kernel. vpnc will error with a reminder if it is missing when vpnc is first run.

Configuring vpnc

The configuration file needs a few pieces of information before vpnc can connect us to the remote network. Edit /etc/vpnc/default.conf to have the following information:

System Message: ERROR/3 (<string>, line 32)

Cannot find pygments lexer for language "vpnc"

.. code-block:: vpnc

    #Interface name tun0
    IPSec gateway 199.17.118.250
    IPSec ID wireless
    IPSec secret REMOVED
    Xauth ${USERNAME} # DragonMail user name
    Xauth ${PASSWORD} # DragonMail password (not required)

Note

Only use the password line if you've secured this configuration and don't want to type a password everytime you connect.

Please, e-mail your name and DragonID to Alex Brandt to request the removed secret.

Thanks to Conor Shenk for decrypting the password.

Checking vpnc

Now, if everything is properly configured and installed then all you need to do is run vpnc as root. If this works, we can set it up so that certain users can run vpnc without becoming root. Otherwise, troubleshoot, check the vpnc homepage, &c.

Add Convenience to vpnc

Autostart vpnc:

If we want vpnc to start on system boot we can add it to our rc.local file. We'll also want to add vpnc-disconnect to the shutdown scripts for the system.
Unprivileged vpnc:

If we would like to run vpnc as a regular user, we'll need to setup a system like sudo. Using visudo, add a line similar to the following to the sudo configuration for your user:
System Message: ERROR/3 (<string>, line 74)

Cannot find pygments lexer for language "sudoers"
```
.. code-block:: sudoers

    USERNAME HOSTNAME = NOPASSWD:/usr/bin/vpnc,/usr/bin/vpnc-disconnect
```
Aliasing vpnc:

Using aliases can make life even easier. Simply add aliases like the following to a .bashrc file to simplify commands requiring the remote network:
```
alias vpnc="sudo vpnc"
alias vpnc-disconnect="sudo vpnc-disconnect"
alias idl="vpnc && idl && vpnc-disconnect"
```

Conclusion

Using vpnc is quite simple and provides convenient access to remote resources securely.