I am trying to establish a VPN connection but I am unable to do so. The issues points to PPP as can be seen in the log output below. However, I am not quite sure what I can make out of this:
/var/log/syslog
Jan 24 11:28:18 sfalk-pc NetworkManager[897]: <info> [1643020098.1871] vpn-connection[0x5602dde346d0,51ea86ae-ed11-459b-9e04-8fa3d6b84810,"iTranslate",0]: Started the VPN service, PID 11309
Jan 24 11:28:18 sfalk-pc NetworkManager[897]: <info> [1643020098.1914] vpn-connection[0x5602dde346d0,51ea86ae-ed11-459b-9e04-8fa3d6b84810,"iTranslate",0]: Saw the service appear; activating connection
Jan 24 11:28:18 sfalk-pc NetworkManager[897]: <info> [1643020098.2245] vpn-connection[0x5602dde346d0,51ea86ae-ed11-459b-9e04-8fa3d6b84810,"iTranslate",0]: VPN connection: (ConnectInteractive) reply received
Jan 24 11:28:18 sfalk-pc nm-l2tp-service[11309]: Check port 1701
Jan 24 11:28:18 sfalk-pc NetworkManager[11325]: Stopping strongSwan IPsec failed: starter is not running
Jan 24 11:28:20 sfalk-pc NetworkManager[11322]: Starting strongSwan 5.8.2 IPsec [starter]...
Jan 24 11:28:20 sfalk-pc NetworkManager[11322]: Loading config setup
Jan 24 11:28:20 sfalk-pc NetworkManager[11322]: Loading conn '51ea86ae-ed11-459b-9e04-8fa3d6b84810'
Jan 24 11:28:20 sfalk-pc charon: 00[DMN] Starting IKE charon daemon (strongSwan 5.8.2, Linux 5.13.0-27-generic, x86_64)
Jan 24 11:28:20 sfalk-pc charon: 00[CFG] loading ca certificates from '/etc/ipsec.d/cacerts'
Jan 24 11:28:20 sfalk-pc charon: 00[CFG] loading aa certificates from '/etc/ipsec.d/aacerts'
Jan 24 11:28:20 sfalk-pc charon: 00[CFG] loading ocsp signer certificates from '/etc/ipsec.d/ocspcerts'
Jan 24 11:28:20 sfalk-pc charon: 00[CFG] loading attribute certificates from '/etc/ipsec.d/acerts'
Jan 24 11:28:20 sfalk-pc charon: 00[CFG] loading crls from '/etc/ipsec.d/crls'
Jan 24 11:28:20 sfalk-pc charon: 00[CFG] loading secrets from '/etc/ipsec.secrets'
Jan 24 11:28:20 sfalk-pc charon: 00[CFG] loading secrets from '/etc/ipsec.d/ipsec.nm-l2tp.secrets'
Jan 24 11:28:20 sfalk-pc charon: 00[CFG] loaded IKE secret for %any
Jan 24 11:28:20 sfalk-pc charon: 00[LIB] loaded plugins: charon aesni aes rc2 sha2 sha1 md5 mgf1 random nonce x509 revocation constraints pubkey pkcs1 pkcs7 pkcs8 pkcs12 pgp dnskey sshkey pem openssl fips-prf gmp agent xcbc hmac gcm drbg attr kernel-netlink resolve socket-default connmark stroke updown eap-mschapv2 xauth-generic counters
Jan 24 11:28:20 sfalk-pc charon: 00[LIB] dropped capabilities, running as uid 0, gid 0
Jan 24 11:28:20 sfalk-pc charon: 00[JOB] spawning 16 worker threads
Jan 24 11:28:20 sfalk-pc charon: 05[CFG] received stroke: add connection '51ea86ae-ed11-459b-9e04-8fa3d6b84810'
Jan 24 11:28:20 sfalk-pc charon: 05[CFG] added configuration '51ea86ae-ed11-459b-9e04-8fa3d6b84810'
Jan 24 11:28:21 sfalk-pc charon: 07[CFG] rereading secrets
Jan 24 11:28:21 sfalk-pc charon: 07[CFG] loading secrets from '/etc/ipsec.secrets'
Jan 24 11:28:21 sfalk-pc charon: 07[CFG] loading secrets from '/etc/ipsec.d/ipsec.nm-l2tp.secrets'
Jan 24 11:28:21 sfalk-pc charon: 07[CFG] loaded IKE secret for %any
Jan 24 11:28:21 sfalk-pc charon: 09[CFG] received stroke: initiate '51ea86ae-ed11-459b-9e04-8fa3d6b84810'
Jan 24 11:28:21 sfalk-pc charon: 11[IKE] initiating Main Mode IKE_SA 51ea86ae-ed11-459b-9e04-8fa3d6b84810[1] to 85.237.31.244
Jan 24 11:28:21 sfalk-pc charon: 11[ENC] generating ID_PROT request 0 [ SA V V V V V ]
Jan 24 11:28:21 sfalk-pc charon: 11[NET] sending packet: from 192.168.178.21[500] to 85.237.31.244[500] (532 bytes)
Jan 24 11:28:21 sfalk-pc charon: 12[NET] received packet: from 85.237.31.244[500] to 192.168.178.21[500] (160 bytes)
Jan 24 11:28:21 sfalk-pc charon: 12[ENC] parsed ID_PROT response 0 [ SA V V V V ]
Jan 24 11:28:21 sfalk-pc charon: 12[IKE] received XAuth vendor ID
Jan 24 11:28:21 sfalk-pc charon: 12[IKE] received DPD vendor ID
Jan 24 11:28:21 sfalk-pc charon: 12[IKE] received FRAGMENTATION vendor ID
Jan 24 11:28:21 sfalk-pc charon: 12[IKE] received NAT-T (RFC 3947) vendor ID
Jan 24 11:28:21 sfalk-pc charon: 12[CFG] selected proposal: IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_2048
Jan 24 11:28:21 sfalk-pc charon: 12[ENC] generating ID_PROT request 0 [ KE No NAT-D NAT-D ]
Jan 24 11:28:21 sfalk-pc charon: 12[NET] sending packet: from 192.168.178.21[500] to 85.237.31.244[500] (396 bytes)
Jan 24 11:28:21 sfalk-pc charon: 13[NET] received packet: from 85.237.31.244[500] to 192.168.178.21[500] (396 bytes)
Jan 24 11:28:21 sfalk-pc charon: 13[ENC] parsed ID_PROT response 0 [ KE No NAT-D NAT-D ]
Jan 24 11:28:21 sfalk-pc charon: 13[IKE] local host is behind NAT, sending keep alives
Jan 24 11:28:21 sfalk-pc charon: 13[ENC] generating ID_PROT request 0 [ ID HASH ]
Jan 24 11:28:21 sfalk-pc charon: 13[NET] sending packet: from 192.168.178.21[4500] to 85.237.31.244[4500] (92 bytes)
Jan 24 11:28:21 sfalk-pc charon: 14[NET] received packet: from 85.237.31.244[4500] to 192.168.178.21[4500] (92 bytes)
Jan 24 11:28:21 sfalk-pc charon: 14[ENC] parsed ID_PROT response 0 [ ID HASH ]
Jan 24 11:28:21 sfalk-pc charon: 14[IKE] IKE_SA 51ea86ae-ed11-459b-9e04-8fa3d6b84810[1] established between 192.168.178.21[192.168.178.21]...85.237.31.244[85.237.31.244]
Jan 24 11:28:21 sfalk-pc charon: 14[IKE] scheduling reauthentication in 9896s
Jan 24 11:28:21 sfalk-pc charon: 14[IKE] maximum IKE_SA lifetime 10436s
Jan 24 11:28:21 sfalk-pc charon: 14[ENC] generating QUICK_MODE request 3179643650 [ HASH SA No ID ID NAT-OA NAT-OA ]
Jan 24 11:28:21 sfalk-pc charon: 14[NET] sending packet: from 192.168.178.21[4500] to 85.237.31.244[4500] (268 bytes)
Jan 24 11:28:21 sfalk-pc charon: 15[NET] received packet: from 85.237.31.244[4500] to 192.168.178.21[4500] (204 bytes)
Jan 24 11:28:21 sfalk-pc charon: 15[ENC] parsed QUICK_MODE response 3179643650 [ HASH SA No ID ID NAT-OA NAT-OA ]
Jan 24 11:28:21 sfalk-pc charon: 15[CFG] selected proposal: ESP:AES_CBC_256/HMAC_SHA1_96/NO_EXT_SEQ
Jan 24 11:28:21 sfalk-pc charon: 15[IKE] CHILD_SA 51ea86ae-ed11-459b-9e04-8fa3d6b84810{1} established with SPIs ca762350_i c44a3336_o and TS 192.168.178.21/32[udp/l2f] === 85.237.31.244/32[udp/l2f]
Jan 24 11:28:21 sfalk-pc charon: 15[ENC] generating QUICK_MODE request 3179643650 [ HASH ]
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: initiating Main Mode IKE_SA 51ea86ae-ed11-459b-9e04-8fa3d6b84810[1] to 85.237.31.244
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: generating ID_PROT request 0 [ SA V V V V V ]
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: sending packet: from 192.168.178.21[500] to 85.237.31.244[500] (532 bytes)
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: received packet: from 85.237.31.244[500] to 192.168.178.21[500] (160 bytes)
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: parsed ID_PROT response 0 [ SA V V V V ]
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: received XAuth vendor ID
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: received DPD vendor ID
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: received FRAGMENTATION vendor ID
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: received NAT-T (RFC 3947) vendor ID
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: selected proposal: IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_2048
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: generating ID_PROT request 0 [ KE No NAT-D NAT-D ]
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: sending packet: from 192.168.178.21[500] to 85.237.31.244[500] (396 bytes)
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: received packet: from 85.237.31.244[500] to 192.168.178.21[500] (396 bytes)
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: parsed ID_PROT response 0 [ KE No NAT-D NAT-D ]
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: local host is behind NAT, sending keep alives
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: generating ID_PROT request 0 [ ID HASH ]
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: sending packet: from 192.168.178.21[4500] to 85.237.31.244[4500] (92 bytes)
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: received packet: from 85.237.31.244[4500] to 192.168.178.21[4500] (92 bytes)
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: parsed ID_PROT response 0 [ ID HASH ]
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: IKE_SA 51ea86ae-ed11-459b-9e04-8fa3d6b84810[1] established between 192.168.178.21[192.168.178.21]...85.237.31.244[85.237.31.244]
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: scheduling reauthentication in 9896s
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: maximum IKE_SA lifetime 10436s
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: generating QUICK_MODE request 3179643650 [ HASH SA No ID ID NAT-OA NAT-OA ]
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: sending packet: from 192.168.178.21[4500] to 85.237.31.244[4500] (268 bytes)
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: received packet: from 85.237.31.244[4500] to 192.168.178.21[4500] (204 bytes)
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: parsed QUICK_MODE response 3179643650 [ HASH SA No ID ID NAT-OA NAT-OA ]
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: selected proposal: ESP:AES_CBC_256/HMAC_SHA1_96/NO_EXT_SEQ
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: CHILD_SA 51ea86ae-ed11-459b-9e04-8fa3d6b84810{1} established with SPIs ca762350_i c44a3336_o and TS 192.168.178.21/32[udp/l2f] === 85.237.31.244/32[udp/l2f]
Jan 24 11:28:21 sfalk-pc NetworkManager[11363]: connection '51ea86ae-ed11-459b-9e04-8fa3d6b84810' established successfully
Jan 24 11:28:21 sfalk-pc charon: 15[NET] sending packet: from 192.168.178.21[4500] to 85.237.31.244[4500] (76 bytes)
Jan 24 11:28:21 sfalk-pc nm-l2tp-service[11309]: xl2tpd started with pid 11369
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: Not looking for kernel SAref support.
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: Using l2tp kernel support.
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: xl2tpd version xl2tpd-1.3.12 started on sfalk-pc PID:11369
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: Written by Mark Spencer, Copyright (C) 1998, Adtran, Inc.
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: Forked by Scott Balmos and David Stipp, (C) 2001
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: Inherited by Jeff McAdams, (C) 2002
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: Forked again by Xelerance (www.xelerance.com) (C) 2006-2016
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: Listening on IP address 0.0.0.0, port 1701
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: Connecting to host 85.237.31.244, port 1701
Jan 24 11:28:21 sfalk-pc NetworkManager[897]: <info> [1643020101.5395] vpn-connection[0x5602dde346d0,51ea86ae-ed11-459b-9e04-8fa3d6b84810,"iTranslate",0]: VPN plugin: state changed: starting (3)
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: Connection established to 85.237.31.244, 1701. Local: 22538, Remote: 56283 (ref=0/0).
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: Calling on tunnel 22538
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: Call established with 85.237.31.244, Local: 29309, Remote: 4754, Serial: 1 (ref=0/0)
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: start_pppd: I'm running:
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: "/usr/sbin/pppd"
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: "plugin"
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: "pppol2tp.so"
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: "pppol2tp"
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: "7"
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: "passive"
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: "nodetach"
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: ":"
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: "file"
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: "/run/nm-l2tp-51ea86ae-ed11-459b-9e04-8fa3d6b84810/ppp-options"
Jan 24 11:28:21 sfalk-pc pppd[11370]: Plugin pppol2tp.so loaded.
Jan 24 11:28:21 sfalk-pc pppd[11370]: Plugin /usr/lib/pppd/2.4.7/nm-l2tp-pppd-plugin.so loaded.
Jan 24 11:28:21 sfalk-pc pppd[11370]: pppd 2.4.7 started by root, uid 0
Jan 24 11:28:21 sfalk-pc pppd[11370]: Using interface ppp0
Jan 24 11:28:21 sfalk-pc pppd[11370]: Connect: ppp0 <-->
Jan 24 11:28:21 sfalk-pc pppd[11370]: Overriding mtu 1500 to 1400
Jan 24 11:28:21 sfalk-pc pppd[11370]: Overriding mru 1500 to mtu value 1400
Jan 24 11:28:21 sfalk-pc NetworkManager[897]: <info> [1643020101.6071] manager: (ppp0): new Ppp device (/org/freedesktop/NetworkManager/Devices/16)
Jan 24 11:28:21 sfalk-pc systemd-udevd[11373]: ethtool: autonegotiation is unset or enabled, the speed and duplex are not writable.
Jan 24 11:28:21 sfalk-pc pppd[11370]: Overriding mtu 1500 to 1400
Jan 24 11:28:21 sfalk-pc pppd[11370]: EAP: Identity prompt "Name"
Jan 24 11:28:21 sfalk-pc pppd[11370]: EAP: peer reports authentication failure
Jan 24 11:28:21 sfalk-pc pppd[11370]: Overriding mtu 1500 to 1400
Jan 24 11:28:21 sfalk-pc pppd[11370]: Overriding mru 1500 to mtu value 1400
Jan 24 11:28:21 sfalk-pc pppd[11370]: Connection terminated.
Jan 24 11:28:21 sfalk-pc charon: 07[KNL] interface ppp0 deleted
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: death_handler: Fatal signal 15 received
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: Terminating pppd: sending TERM signal to pid 11370
Jan 24 11:28:21 sfalk-pc NetworkManager[11369]: xl2tpd[11369]: Connection 56283 closed to 85.237.31.244, port 1701 (Server closing)
Jan 24 11:28:21 sfalk-pc NetworkManager[897]: <warn> [1643020101.6916] vpn-connection[0x5602dde346d0,51ea86ae-ed11-459b-9e04-8fa3d6b84810,"iTranslate",0]: VPN plugin: failed: connect-failed (1)
Jan 24 11:28:21 sfalk-pc NetworkManager[897]: <info> [1643020101.6918] vpn-connection[0x5602dde346d0,51ea86ae-ed11-459b-9e04-8fa3d6b84810,"iTranslate",0]: VPN plugin: state changed: stopping (5)
Jan 24 11:28:21 sfalk-pc NetworkManager[11380]: Stopping strongSwan IPsec...
Jan 24 11:28:21 sfalk-pc gnome-shell[2136]: Removing a network device that was not added
Jan 24 11:28:21 sfalk-pc gnome-shell[1370]: Removing a network device that was not added
Jan 24 11:28:21 sfalk-pc charon: 00[DMN] signal of type SIGINT received. Shutting down
Jan 24 11:28:21 sfalk-pc charon: 00[IKE] closing CHILD_SA 51ea86ae-ed11-459b-9e04-8fa3d6b84810{1} with SPIs ca762350_i (449 bytes) c44a3336_o (554 bytes) and TS 192.168.178.21/32[udp/l2f] === 85.237.31.244/32[udp/l2f]
Jan 24 11:28:21 sfalk-pc charon: 00[IKE] sending DELETE for ESP CHILD_SA with SPI ca762350
Jan 24 11:28:21 sfalk-pc charon: 00[ENC] generating INFORMATIONAL_V1 request 3062397126 [ HASH D ]
Jan 24 11:28:21 sfalk-pc charon: 00[NET] sending packet: from 192.168.178.21[4500] to 85.237.31.244[4500] (92 bytes)
Jan 24 11:28:21 sfalk-pc charon: 00[IKE] deleting IKE_SA 51ea86ae-ed11-459b-9e04-8fa3d6b84810[1] between 192.168.178.21[192.168.178.21]...85.237.31.244[85.237.31.244]
Jan 24 11:28:21 sfalk-pc charon: 00[IKE] sending DELETE for IKE_SA 51ea86ae-ed11-459b-9e04-8fa3d6b84810[1]
Jan 24 11:28:21 sfalk-pc charon: 00[ENC] generating INFORMATIONAL_V1 request 441330021 [ HASH D ]
Jan 24 11:28:21 sfalk-pc charon: 00[NET] sending packet: from 192.168.178.21[4500] to 85.237.31.244[4500] (108 bytes)
Jan 24 11:28:21 sfalk-pc pppd[11370]: Exit.
Jan 24 11:28:21 sfalk-pc nm-l2tp-service[11309]: ipsec shut down
Jan 24 11:28:21 sfalk-pc NetworkManager[897]: <info> [1643020101.8102] vpn-connection[0x5602dde346d0,51ea86ae-ed11-459b-9e04-8fa3d6b84810,"iTranslate",0]: VPN plugin: state changed: stopped (6)
Jan 24 11:28:21 sfalk-pc NetworkManager[897]: <info> [1643020101.8173] vpn-connection[0x5602dde346d0,51ea86ae-ed11-459b-9e04-8fa3d6b84810,"iTranslate",0]: VPN service disappeared
Jan 24 11:28:21 sfalk-pc org.kde.kdeconnect.daemon.desktop[2345]: "No such interface “org.freedesktop.DBus.Properties” on object at path /org/freedesktop/NetworkManager/ActiveConnection/16"
Jan 24 11:28:21 sfalk-pc org.kde.kdeconnect.daemon.desktop[2345]: message repeated 2 times: [ "No such interface “org.freedesktop.DBus.Properties” on object at path /org/freedesktop/NetworkManager/ActiveConnection/16"]
Jan 24 11:29:26 sfalk-pc gnome-shell[2136]: ../clutter/clutter/clutter-actor.c:10558: The clutter_actor_set_allocation() function can only be called from within the implementation of the ClutterActor::allocate() virtual function.
Jan 24 11:30:01 sfalk-pc CRON[11408]: (root) CMD ([ -x /etc/init.d/anacron ] && if [ ! -d /run/systemd/system ]; then /usr/sbin/invoke-rc.d anacron start >/dev/null; fi)
Jan 24 11:30:57 sfalk-pc systemd-timesyncd[838]: Initial synchronization to time server 91.189.89.199:123 (ntp.ubuntu.com).
Jan 24 11:33:17 sfalk-pc systemd[1]: Started Run anacron jobs.
Jan 24 11:33:17 sfalk-pc systemd[1]: anacron.service: Succeeded.
Jan 24 11:33:17 sfalk-pc anacron[11474]: Anacron 2.3 started on 2022-01-24
Jan 24 11:33:17 sfalk-pc anacron[11474]: Normal exit (0 jobs run)
Jan 24 11:35:01 sfalk-pc CRON[11706]: (root) CMD (command -v debian-sa1 > /dev/null && debian-sa1 1 1)
Jan 24 11:35:18 sfalk-pc wpa_supplicant[935]: wlp5s0: WPA: Group rekeying completed with 3c:37:12:5b:9f:4d [GTK=CCMP]
