SSTP doesn't work with IPv6

[Wojciech]

When connecting to a server that offers IPv6 inside the tunnel (required on the server) the connection is not established.

Logs from client:

Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P pppd[13363]: Plugin /usr/lib/pppd/2.4.7/nm-sstp-pppd-plugin.so loaded.
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P NetworkManager[1001]: Plugin /usr/lib/pppd/2.4.7/nm-sstp-pppd-plugin.so loaded.
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P pppd[13363]: pppd 2.4.7 started by root, uid 0
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P NetworkManager[1001]: <info> [1556185462.0074] manager: (ppp0): new Ppp device (/org/freedesktop/NetworkManager/Devices/10)
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P pppd[13363]: Using interface ppp0
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P NetworkManager[1001]: Using interface ppp0
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P NetworkManager[1001]: Connect: ppp0 <--> /dev/pts/2
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P systemd-udevd[13367]: link_config: autonegotiation is unset or enabled, the speed and duplex are not writable.
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P pppd[13363]: Connect: ppp0 <--> /dev/pts/2
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P NetworkManager[1001]: <info> [1556185462.0217] devices added (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P NetworkManager[1001]: <info> [1556185462.0218] device added (path: /sys/devices/virtual/net/ppp0, iface: ppp0): no ifupdown configuration found.
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P pppd[13363]: CHAP authentication succeeded
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P NetworkManager[1001]: CHAP authentication succeeded
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P pppd[13363]: LCP terminated by peer (IPv6 negotiation rejected)
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P NetworkManager[1001]: LCP terminated by peer (IPv6 negotiation rejected)
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P sstpc[13368]: Unrecoverable SSL error
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P sstpc[13368]: Connection was aborted, Unknown Status Attribute
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P pppd[13363]: Modem hangup
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P NetworkManager[1001]: Modem hangup
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P NetworkManager[1001]: Connection terminated.
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P pppd[13363]: Connection terminated.
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P charon-nm: 09[KNL] interface ppp0 deleted
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P charon: 15[KNL] interface ppp0 deleted
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P NetworkManager[1001]: <info> [1556185462.3353] devices removed (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P NetworkManager[1001]: <info> [1556185462.3391] vpn-connection[0x562289b7c100,cf9d7170-397b-47d9-9831-15fd6c07a5ed,"VPN 1",0]: VPN service disappeared
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P pppd[13363]: Exit.
Apr 25 11:44:22 wmanka-Lenovo-IdeaPad-Y510P gnome-shell[3006]: Removing a network device that was not added

Logs from server site (MikroTik RouterOS 6.44.3):

09:47:14 sstp,ppp,debug : LCP lowerup
09:47:14 sstp,ppp,debug : LCP open
09:47:15 sstp,ppp,debug : LCP opened
09:47:15 sstp,ppp,info,account wmanka logged in, 10.10.10.2
09:47:15 sstp,ppp,info <sstp-wmanka>: authenticated
09:47:15 sstp,ppp,debug <sstp-wmanka>: IPCP lowerup
09:47:15 sstp,ppp,debug <sstp-wmanka>: IPCP open
09:47:15 sstp,ppp,debug <sstp-wmanka>: IPV6CP lowerup
09:47:15 sstp,ppp,debug <sstp-wmanka>: IPV6CP open
09:47:15 sstp,ppp,debug <sstp-wmanka>: MPLSCP open
09:47:15 sstp,ppp,debug <sstp-wmanka>: BCP open
09:47:15 sstp,ppp,debug <sstp-wmanka>: CCP lowerup
09:47:15 sstp,ppp,debug <sstp-wmanka>: CCP open
09:47:15 sstp,ppp,debug <sstp-wmanka>: received unsupported protocol 0x80fd
09:47:15 sstp,ppp,debug <sstp-wmanka>: LCP close
09:47:15 sstp,ppp,debug <sstp-wmanka>: LCP closed
09:47:15 sstp,ppp,debug <sstp-wmanka>: CCP lowerdown
09:47:15 sstp,ppp,debug <sstp-wmanka>: BCP lowerdown
09:47:15 sstp,ppp,debug <sstp-wmanka>: BCP down event in starting state
09:47:15 sstp,ppp,debug <sstp-wmanka>: IPCP lowerdown
09:47:15 sstp,ppp,debug <sstp-wmanka>: IPV6CP lowerdown
09:47:15 sstp,ppp,debug <sstp-wmanka>: MPLSCP lowerdown
09:47:15 sstp,ppp,debug <sstp-wmanka>: MPLSCP down event in starting state
09:47:15 sstp,ppp,debug <sstp-wmanka>: PPP received non-LCP packet (0x8021) when LCP not open
09:47:15 sstp,ppp,debug <sstp-wmanka>: PPP received non-LCP packet (0x8021) when LCP not open
09:47:15 sstp,ppp,debug <sstp-wmanka>: LCP lowerdown
09:47:15 sstp,ppp,debug <sstp-wmanka>: CCP close
09:47:15 sstp,ppp,debug <sstp-wmanka>: BCP close
09:47:15 sstp,ppp,debug <sstp-wmanka>: IPCP close
09:47:15 sstp,ppp,debug <sstp-wmanka>: IPV6CP close
09:47:15 sstp,ppp,debug <sstp-wmanka>: MPLSCP close
09:47:15 sstp,ppp,info <sstp-wmanka>: terminating... - IPv6 negotiation rejected
09:47:15 sstp,ppp,debug <sstp-wmanka>: LCP lowerdown
09:47:15 sstp,ppp,debug <sstp-wmanka>: LCP down event in initial state
09:47:15 sstp,ppp,info,account wmanka logged out, 0 69 40 4 3
09:47:15 sstp,ppp,info <sstp-wmanka>: disconnected

[Eivind Naess (eivnaes)]

Interesting, it could possibly look like some ipv6 related options isn't present in the client configuration and thus the client rejects the IPv6 negotiation.

[Anton Melnichuk (bezdna)]

same thing. disable IPv6 configuration for connection. and now work