NetworkManager PPTP plugin connections only works for some apps

Binary package hint: network-manager-pptp

The connection that the n-m pptp plugin is creating doesn't work for all apps.
In my case, my ISP requires using a pptp connection to get an external IP address. The instructions it gives to connect are for Windows and they don't show any additional configurations beside the default ones.

I have tried with the default options which nm-pptp dialog sets, and I have tried toggling many options in the n-m config dialogs, but it still gave me the same responses. The options I ended up with are in the attached file.

The problem is that for some programs, the vpn connection works, i.e. firefox, pidgin, amule, evolution, but for some it doesn't, i.e. amsn, empathy. The messengers used were MSN, so Empathy with msn and amsn doesn't work, but pidgin with msn does.

The connections seems to work just fine as far as the nm-applet is concerned, and syslog shows me the following:

----------------------------------------8<-------------------------------------------------
Jun 26 19:35:55 razor NetworkManager: <info> Will activate VPN connection 'PredialNet', service 'org.freedesktop.NetworkManager.ppp_starter', user_name 'ronan', vpn_data 'ppp-connection-type / pptp / pptp-remote / 172.16.10.35 / usepeerdns / yes / encrypt-mppe / yes / encrypt-mppe-128 / yes / encrypt-mppe-stateful / no / compress-mppc / no / compress-deflate / no / compress-bsd / no / ppp-lock / yes / ppp-auth-peer / no / ppp-refuse-eap / yes / ppp-refuse-chap / yes / ppp-refuse-mschap / yes / mtu / 1500 / mru / 1500 / lcp-echo-failure / 10 / lcp-echo-interval / 30 / ppp-extra / / ppp-debug / no / usepeerdns-overtunnel / no / routes / / use-routes / no', route ''.
Jun 26 19:35:55 razor NetworkManager: <info> VPN Activation (PredialNet) Stage 2 of 4 (Connection Prepare Wait) scheduled...
Jun 26 19:35:55 razor NetworkManager: <info> VPN Activation (PredialNet) Stage 2 of 4 (Connection Prepare Wait) waiting...
Jun 26 19:35:55 razor NetworkManager: <info> VPN Activation (PredialNet) Stage 2 of 4 (Connection Prepare Wait) complete.
Jun 26 19:35:55 razor NetworkManager: <info> VPN Activation (PredialNet) Stage 3 of 4 (Connect) scheduled...
Jun 26 19:35:55 razor NetworkManager: <info> VPN Activation (PredialNet) Stage 3 of 4 (Connect) sending connect request.
Jun 26 19:35:55 razor NetworkManager: <info> VPN Activation (PredialNet) Stage 3 of 4 (Connect) request sent, waiting for reply...
Jun 26 19:35:55 razor NetworkManager: <info> VPN service 'org.freedesktop.NetworkManager.ppp_starter' signaled state change 6 -> 3.
Jun 26 19:35:55 razor NetworkManager: <info> VPN Activation (PredialNet) Stage 3 of 4 (Connect) reply received.
Jun 26 19:35:55 razor NetworkManager: <info> VPN Activation (PredialNet) Stage 4 of 4 (IP Config Get) timeout scheduled...
Jun 26 19:35:55 razor NetworkManager: <info> VPN Activation (PredialNet) Stage 3 of 4 (Connect) complete, waiting for IP configuration...
Jun 26 19:35:55 razor pppd[14793]: Plugin nm-pppd-plugin.so loaded.
Jun 26 19:35:55 razor pppd[14793]: nm-pppd-plugin: plugin initialized.
Jun 26 19:35:55 razor pppd[14794]: pppd 2.4.4 started by root, uid 0
Jun 26 19:35:55 razor pptp[14796]: anon log[main:pptp.c:267]: The synchronous pptp option is NOT activated
Jun 26 19:35:55 razor pppd[14794]: Using interface ppp0
Jun 26 19:35:55 razor pppd[14794]: Connect: ppp0 <--> /dev/pts/1
Jun 26 19:35:55 razor pptp[14799]: anon log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 1 'Start-Control-Connection-Request'
Jun 26 19:35:55 razor pptp[14799]: anon log[ctrlp_disp:pptp_ctrl.c:738]: Received Start Control Connection Reply
Jun 26 19:35:55 razor pptp[14799]: anon log[ctrlp_disp:pptp_ctrl.c:772]: Client connection established.
Jun 26 19:35:56 razor pppd[14794]: nm-pppd-plugin: CHAP check hook.
Jun 26 19:35:56 razor pptp[14799]: anon log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 7 'Outgoing-Call-Request'
Jun 26 19:35:56 razor pptp[14799]: anon log[ctrlp_disp:pptp_ctrl.c:857]: Received Outgoing Call Reply.
Jun 26 19:35:56 razor pptp[14799]: anon log[ctrlp_disp:pptp_ctrl.c:896]: Outgoing call established (call ID 0, peer's call ID 7129).
Jun 26 19:35:56 razor pptp[14799]: anon log[ctrlp_disp:pptp_ctrl.c:949]: PPTP_SET_LINK_INFO received from peer_callid 0
Jun 26 19:35:56 razor pptp[14799]: anon log[ctrlp_disp:pptp_ctrl.c:952]: send_accm is 00000000, recv_accm is FFFFFFFF
Jun 26 19:35:56 razor pptp[14799]: anon warn[ctrlp_disp:pptp_ctrl.c:955]: Non-zero Async Control Character Maps are not supported!
Jun 26 19:35:56 razor pppd[14794]: nm-pppd-plugin: CHAP credentials requested.
Jun 26 19:35:56 razor pppd[14794]: CHAP authentication succeeded
Jun 26 19:35:56 razor pppd[14794]: MPPE 128-bit stateless compression enabled
Jun 26 19:35:58 razor pppd[14794]: Cannot determine ethernet address for proxy ARP
Jun 26 19:35:58 razor pppd[14794]: local IP address 189.1.138.13
Jun 26 19:35:58 razor pppd[14794]: remote IP address 189.1.129.4
Jun 26 19:35:58 razor NetworkManager: <info> VPN Activation (PredialNet) Stage 4 of 4 (IP Config Get) reply received.
Jun 26 19:35:58 razor NetworkManager: <WARN> nm_system_device_set_ip4_route(): Failed to set IPv4 default route on 'wlan0': File exists
Jun 26 19:35:59 razor NetworkManager: <info> Clearing nscd hosts cache.
Jun 26 19:35:59 razor NetworkManager: <WARN> nm_spawn_process(): nm_spawn_process('/usr/sbin/nscd -i hosts'): could not spawn process. (Failed to execute child process "/usr/sbin/nscd" (No such file or directory))
Jun 26 19:35:59 razor NetworkManager: <info> VPN Activation (PredialNet) Stage 4 of 4 (IP Config Get) complete.
Jun 26 19:35:59 razor NetworkManager: <info> VPN Activation (PredialNet) successful.
Jun 26 19:35:59 razor NetworkManager: <info> VPN service 'org.freedesktop.NetworkManager.ppp_starter' signaled state change 3 -> 4.
Jun 26 19:36:55 razor pptp[14799]: anon log[logecho:pptp_ctrl.c:676]: Echo Request received.
Jun 26 19:36:55 razor pptp[14799]: anon log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 6 'Echo-Reply'
Jun 26 19:37:55 razor pptp[14799]: anon log[logecho:pptp_ctrl.c:676]: Echo Request received.
Jun 26 19:37:55 razor pptp[14799]: anon log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 6 'Echo-Reply'
Jun 26 19:37:55 razor pptp[14799]: anon log[logecho:pptp_ctrl.c:676]: Echo Reply received.
Jun 26 19:38:55 razor pptp[14799]: anon log[logecho:pptp_ctrl.c:676]: Echo Reply received.
Jun 26 19:39:36 razor pptp[14796]: anon log[decaps_gre:pptp_gre.c:407]: buffering packet 220 (expecting 219, lost or reordered)
-------------------------8<-------------------------8<--------------------------------
And many other messages like the last ones.

The strange thing is that if I set ppp up manually the vpn works fine for everything. The config file I used was:

-----------------------8<-------------------------8<-------------------------
remotename predial
linkname predial
ipparam predial
pty "pptp 172.16.10.35 --nolaunchpppd "
name conectar
usepeerdns
require-mppe
refuse-eap
noauth

# adopt defaults from the pptp-linux package
file /etc/ppp/options.pptp
------------------------8<-----------------------8<-----------------------------
and manually routing with:
sudo route add -host 172.16.10.35 gw router wlan0
sudo route add default ppp0
which I also put on /etc/ppp/ip-up.d/predial so it would execute automatically when the connection goes up.
To open the connection, I use:
sudo pon predial nodetach
which gives me the following output:
------------------------8<------------------------8<-------------------------------
Using interface ppp0
Connect: ppp0 <--> /dev/pts/1
CHAP authentication succeeded
MPPE 128-bit stateless compression enabled
Cannot determine ethernet address for proxy ARP
local IP address 189.1.129.204
remote IP address 189.1.129.4
-----------------------8<-------------------------8<------------------------------
which is very similar to some lines in the nm output.

Note that I have also tried to manually set the route after the connection with nm, so that it would look exactly like the routes I get using pptp manually, but that also didn't help. Also, the last options I tried in the config dialog are the closest I could get to the options set up in /etc/ppp/peers/predial and /etc/ppp/options.pptp, but that didn't help either.

I'm using Ubuntu Hardy Heron 8.04.