This might be related to 638909 but I think it's a more general problem to VPN and the dispatcher than to any particular VPN implementation.

The issue is basically that a dispatcher script for a VPN connection (i.e. in /etc/NetworkManager/dispatcher.d/) is given an environment such as:

CONNECTION_UUID='266b51c6-948f-48df-9e44-b6e42a1d6c60'
DHCP4_BROADCAST_ADDRESS='10.75.23.255'
DHCP4_DHCP_LEASE_TIME='3600'
DHCP4_DHCP_MESSAGE_TYPE='5'
DHCP4_DHCP_REBINDING_TIME='3150'
DHCP4_DHCP_RENEWAL_TIME='1800'
DHCP4_DHCP_SERVER_IDENTIFIER='10.75.23.254'
DHCP4_DOMAIN_NAME='ilinx'
DHCP4_DOMAIN_NAME_SERVERS='10.75.23.254'
DHCP4_DOMAIN_SEARCH='ilinx.'
DHCP4_EXPIRY='1303398164'
DHCP4_HOST_NAME='brian-laptop'
DHCP4_IP_ADDRESS='10.75.23.193'
DHCP4_NETWORK_NUMBER='10.75.23.0'
DHCP4_NTP_SERVERS='66.96.30.91 72.1.194.82 216.234.161.11 209.139.208.96 24.215.0.24'
DHCP4_ROUTERS='10.75.23.254'
DHCP4_SUBNET_MASK='255.255.255.0'
IFS=' 	
'
IP4_ADDRESS_0='10.75.23.193/24 10.75.23.254'
IP4_DOMAINS='ilinx'
IP4_NAMESERVERS='10.75.23.254'
IP4_NUM_ADDRESSES='1'
IP4_NUM_ROUTES='0'
OPTIND='1'
PATH='/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin'
PPID='6564'
PS1='# '
PS2='> '
PS4='+ '
PWD='/'

The problem is that those values are for the physical interface not for the VPN interface.  In the above, at minimum, IP4_ADDRESS_0 should be the address of the VPN interface, IP4_DOMAINS should be the domains assigned by the VPN server or entered into the NM configuration for the VPN if applicable, and IP4_NAMESERVERS should be the nameservers assigned by the VPN server, or again, entered by the user in the NM settings for the VPN.

Giving out the physical interfaces values for these settings is entirely incorrect.

Additionally, if any classless routing information is sent by the VPN server, or if the user has entered any routes in the IPV4 Settings->Routes... configuration, it would be nice to have those reported in the dispatcher environment.