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# vpnc

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vpnc[dead link 2021-11-19 ⓘ] is a VPN client for Cisco hardware VPNs.

## Installation

Install the vpnc package.

## Configuration

The vpnc configuration files are in `/etc/vpnc`. It contains a `default.conf` file that you can copy and modify for your setup.

Executing `vpnc --long-help` will provide the names and descriptions of the various configuration options. For instance, in that output you will see

     --gateway <ip/hostname>
         IP/name of your IPSec gateway
     conf-variable: IPSec gateway<ip/hostname>

which translates into a line like this in your configuration file:

    IPSec gateway gateway.example.com

## Starting

The `vpnc` package comes with a systemd unit `vpnc@.service`. If you want to use the configuration file `/etc/vpnc/client.conf`, you would start it with `systemctl start vpnc@client`.

## Troubleshooting

In case the vpnc client crashes with:

       May 15 09:11:38 ntrp-mimacom systemd-coredump[5858]: Process 5814 (vpnc) of user 0 dumped core.

                                                            Stack trace of thread 5814:
                                                            #0  0x00007f835cba3a10 raise (libc.so.6)
                                                            #1  0x00007f835cba513a abort (libc.so.6)
                                                            #2  0x00007f835cb9c607 __assert_fail_base (libc.so.6)
                                                            #3  0x00007f835cb9c6b2 __assert_fail (libc.so.6)
                                                            #4  0x000000000040e48c n/a (vpnc)
                                                            #5  0x0000000000412348 n/a (vpnc)
                                                            #6  0x0000000000404f72 n/a (vpnc)
                                                            #7  0x00007f835cb90511 __libc_start_main (libc.so.6)
                                                            #8  0x000000000040596a n/a (vpnc)

you will need to monkey patch the the software because an assertion is failing with the latest updates..

Download the sources from https://svn.unix-ag.uni-kl.de/vpnc/trunk/[dead link 2021-11-19 ⓘ] and patch the file vpnc.c with the following:

       Index: vpnc.c
       ===================================================================
       --- vpnc.c      (revision 550)
       +++ vpnc.c      (working copy)
       @@ -1206,7 +1206,7 @@
               assert(a->af == isakmp_attr_16);
               assert(a->u.attr_16 == IKE_LIFE_TYPE_SECONDS || a->u.attr_16 == IKE_LIFE_TYPE_K);
               assert(a->next != NULL);
       -       assert(a->next->type == IKE_ATTRIB_LIFE_DURATION);
       +       /* assert(a->next->type == IKE_ATTRIB_LIFE_DURATION); */

               if (a->next->af == isakmp_attr_16)
                       value = a->next->u.attr_16;

Temporary workaround found here: https://bbs.archlinux.org/viewtopic.php?id=225556

Remember to change the PREFIX to /usr instead /usr/local so you overwrite the broken binary.

Category:

- Virtual Private Network

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