This bug is affecting me as well. It's annoying not being able to connect to my work VPN. Since nobody wants to follow this bug up. Here is the snippet of the log:
ct 6 01:37:00 reza pppd[18741]: Plugin /usr/lib/pppd/2.4.7/nm-pptp-pppd-plugin.so loaded. Oct 6 01:37:00 reza NetworkManager[18741]: Plugin /usr/lib/pppd/2.4.7/nm-pptp-pppd-plugin.so loaded. Oct 6 01:37:00 reza pppd[18741]: pppd 2.4.7 started by root, uid 0 Oct 6 01:37:00 reza pppd[18741]: Using interface ppp0 Oct 6 01:37:00 reza NetworkManager[18741]: Using interface ppp0 Oct 6 01:37:00 reza NetworkManager[18741]: Connect: ppp0 <--> /dev/pts/3 Oct 6 01:37:00 reza pppd[18741]: Connect: ppp0 <--> /dev/pts/3 Oct 6 01:37:00 reza NetworkManager[16794]: <info> [1601919420.1914] manager: (ppp0): new Ppp device (/org/freedesktop/NetworkManager/Devices/22) Oct 6 01:37:00 reza pptp[18746]: nm-pptp-service-18737 log[main:pptp.c:353]: The synchronous pptp option is NOT activated Oct 6 01:37:00 reza systemd-udevd[18745]: ethtool: autonegotiation is unset or enabled, the speed and duplex are not writable. Oct 6 01:37:00 reza pptp[18758]: nm-pptp-service-18737 log[ctrlp_rep:pptp_ctrl.c:258]: Sent control packet type is 1 'Start-Control-Connection-Request' Oct 6 01:37:00 reza pptp[18758]: nm-pptp-service-18737 log[ctrlp_disp:pptp_ctrl.c:781]: Received Start Control Connection Reply Oct 6 01:37:00 reza pptp[18758]: nm-pptp-service-18737 log[ctrlp_disp:pptp_ctrl.c:815]: Client connection established. Oct 6 01:37:01 reza pptp[18758]: nm-pptp-service-18737 log[ctrlp_rep:pptp_ctrl.c:258]: Sent control packet type is 7 'Outgoing-Call-Request' Oct 6 01:37:01 reza pptp[18758]: nm-pptp-service-18737 log[ctrlp_disp:pptp_ctrl.c:900]: Received Outgoing Call Reply. Oct 6 01:37:01 reza pptp[18758]: nm-pptp-service-18737 log[ctrlp_disp:pptp_ctrl.c:938]: Outgoing call established (call ID 60622, peer's call ID 6890). Oct 6 01:37:01 reza pptp[18758]: nm-pptp-service-18737 log[ctrlp_disp:pptp_ctrl.c:1004]: PPTP_SET_LINK_INFO received from peer_callid 40298 Oct 6 01:37:01 reza pptp[18758]: nm-pptp-service-18737 log[ctrlp_disp:pptp_ctrl.c:1006]: send_accm is 00000000, recv_accm is FFFFFFFF Oct 6 01:37:01 reza pptp[18758]: nm-pptp-service-18737 warn[ctrlp_disp:pptp_ctrl.c:1011]: Non-zero Async Control Character Maps are not supported! Oct 6 01:37:01 reza pppd[18741]: MS-CHAPv2 Success packet is badly formed. Oct 6 01:37:01 reza NetworkManager[18741]: MS-CHAPv2 Success packet is badly formed. Oct 6 01:37:01 reza NetworkManager[18741]: CHAP authentication failed Oct 6 01:37:01 reza pppd[18741]: CHAP authentication failed Oct 6 01:37:01 reza pptp[18758]: nm-pptp-service-18737 log[ctrlp_disp:pptp_ctrl.c:1004]: PPTP_SET_LINK_INFO received from peer_callid 40298 Oct 6 01:37:01 reza pptp[18758]: nm-pptp-service-18737 log[ctrlp_disp:pptp_ctrl.c:1006]: send_accm is FFFFFFFF, recv_accm is FFFFFFFF Oct 6 01:37:01 reza NetworkManager[18741]: Connection terminated. Oct 6 01:37:01 reza pptp[18758]: nm-pptp-service-18737 warn[ctrlp_disp:pptp_ctrl.c:1011]: Non-zero Async Control Character Maps are not supported! Oct 6 01:37:01 reza pppd[18741]: Connection terminated. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to ppp in Ubuntu. https://bugs.launchpad.net/bugs/1890814 Title: Handle PPP non-compliant success packets Status in ppp package in Ubuntu: Confirmed Status in ppp package in Debian: Unknown Bug description: [Impact] According to RFC2759, the format of PPP success packets is : "S=<auth_string> M=<message>" Recently Windows Server 2019 has started producing non-complaint PPP success packets which have a space missing before the M= characters. PPP based (e.g. PPTP, L2TP, etc) VPN clients connecting to an affected Windows Server 2019 VPN server will get the following error message during MS-CHAPv2 authentication : MS-CHAPv2 Success packet is badly formed If the following upstream ppp patch is applied, it will handle the non-compliant, missing-space before M= success packets : https://github.com/paulusmack/ppp/commit/3cd95baf3f1de1d5a9bc89be0f4c3215ceb5aefe.patch To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ppp/+bug/1890814/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp