VPN fails silently if peer uses 1DES

[Daniël van Eeden]

I needed to connect to a Cisco VPN. I imported a pcf file, but after that the VPN failed. After testing with the vpnc commandline client it seems that the VPN concentrator is configured for 1DES and that vpnc disables that by default (which is good).

The error from vpnc
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vpnc: peer selected (single) DES as "encryption" method.
This algorithm is considered too weak today
If your vpn concentrator admin still insists on using DES
use the "--enable-1des" option
------------------------------------------------

The setting as described in the manpage.
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       --enable-1des
              enables weak single DES encryption
       conf-variable: Enable Single DES
------------------------------------------------

After setting the option to enable single DES the VPN worked.

Then I went to the network manager settings: VPN->Advanced->Encryption Method and I changed it to 'Weak'. Then it VPN worked.

What I expect if I connect to a 1DES Cisco VPN with the default settings is:
- NetworkManager detects that the encryption method doesn't match and gives an error like "Encryption method mismatch: Local=Strong Remote=Weak, Go to advanced settings to change it" (Or a warning like "Remote VPN is configured for weak encryption: Continue or Abort?")

[Daniël van Eeden (dveeden)]

Versions:
network-manager-vpnc 0.9.6.0-0ubuntu2
network-manager 0.9.8.0-0ubuntu6
Ubuntu 13.04

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[ariel cornejo (arielco)]

Indeed, it even shows the usual "VPN connection has been successfully established" notification followed by another that says "The VPN connection 'x' failed". I can't find a relevant message in syslog.