impossible to connect tunnel: socket(AF_PPPOX) failed: Protocol not supported

L2TP related questions
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edelwi
Posts: 2
Joined: 08 Apr 2020, 07:58

impossible to connect tunnel: socket(AF_PPPOX) failed: Protocol not supported

Post by edelwi »

Hi,
help me please, i can`t setup l2tp on Centos 8 with accel-ppp and strongswan. I get that messages (accel-ppp.log) when i try to connect from Windows 10:
[2020-04-07 19:51:29]: info: l2tp: recv [L2TP tid=0 sid=0 Ns=0 Nr=0 <Message-Type Start-Ctrl-Conn-Request> <Protocol-Version 256> <Framing-Capabilities 1> <Bearer-Capabilities 0> <Firmware-Revision 2560> <Host-Name DESKTOP-EGB93TB> <Vendor-Name Microsoft> <Assigned-Tunnel-ID 4> <Recv-Window-Size 8>]
[2020-04-07 19:51:29]: info: l2tp: handling SCCRQ from 85.xx.xx.xx
[2020-04-07 19:51:29]: info: l2tp: new tunnel 49443-4 created following reception of SCCRQ from 85.xx.xx.xx:1701
[2020-04-07 19:51:29]: info: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): sending SCCRP
[2020-04-07 19:51:29]: info: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): send [L2TP tid=4 sid=0 Ns=0 Nr=1 <Message-Type Start-Ctrl-Conn-Reply> <Protocol-Version 256> <Host-Name domain.example.com> <Framing-Capabilities 1> <Assigned-Tunnel-ID -16093> <Vendor-Name accel-ppp> <Recv-Window-Size 16>]
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): 1 message sent from send queue
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): handling ZLB
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): recv [L2TP tid=49443 sid=0 Ns=3 Nr=1]
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): 1 message added to reception queue
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): 1 message acked by peer
[2020-04-07 19:51:29]: info: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): recv [L2TP tid=49443 sid=0 Ns=1 Nr=1 <Message-Type Start-Ctrl-Conn-Connected>]
[2020-04-07 19:51:29]: info: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): handling SCCCN
[2020-04-07 19:51:29]: error: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): impossible to connect tunnel: socket(AF_PPPOX) failed: Protocol not supported
[2020-04-07 19:51:29]: error: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): impossible to handle SCCCN: connecting tunnel failed, disconnecting tunnel
[2020-04-07 19:51:29]: info: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): sending StopCCN (res: 2, err: 0)
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): 1 message processed from reception queue
[2020-04-07 19:51:29]: info: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): send [L2TP tid=4 sid=0 Ns=1 Nr=2 <Message-Type Stop-Ctrl-Conn-Notify> <Assigned-Tunnel-ID -16093> <Result-Code>]
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): 1 message sent from send queue
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): 1 message added to reception queue
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): 0 message acked by peer
[2020-04-07 19:51:29]: info: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): discarding message received while disconnecting
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): 1 message processed from reception queue
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): 0 message sent from send queue
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): sending ZLB
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): send [L2TP tid=4 sid=0 Ns=2 Nr=3]
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): handling ZLB
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): recv [L2TP tid=49443 sid=0 Ns=3 Nr=2]
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): 0 message added to reception queue
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): 1 message acked by peer
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): 0 message processed from reception queue
[2020-04-07 19:51:29]: debug: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): 0 message sent from send queue
[2020-04-07 19:51:29]: info: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): tunnel disconnection acknowledged by peer, deleting tunnel
[2020-04-07 19:51:29]: info: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): deleting tunnel
[2020-04-07 19:51:29]: info: l2tp tunnel 49443-4 (85.xx.xx.xx:1701): tunnel destroyed
and when i try to connect from Ubuntu:
[2020-04-07 19:53:32]: info: l2tp: recv [L2TP tid=0 sid=0 Ns=0 Nr=0 <Message-Type Start-Ctrl-Conn-Request> <Protocol-Version 256> <Framing-Capabilities 3> <Bearer-Capabilities 0> <Firmware-Revision 1680> <Host-Name ahost-x555b> <Vendor-Name xelerance.com> <Assigned-Tunnel-ID -21771> <Recv-Window-Size 8>]
[2020-04-07 19:53:32]: info: l2tp: handling SCCRQ from 82.xx.xx.xx
[2020-04-07 19:53:32]: info: l2tp: new tunnel 6233-43765 created following reception of SCCRQ from 82.xx.xx.xx:39501
[2020-04-07 19:53:32]: info: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): sending SCCRP
[2020-04-07 19:53:32]: info: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): send [L2TP tid=43765 sid=0 Ns=0 Nr=1 <Message-Type Start-Ctrl-Conn-Reply> <Protocol-Version 256> <Host-Name domain.example.com> <Framing-Capabilities 3> <Assigned-Tunnel-ID 6233> <Vendor-Name accel-ppp> <Recv-Window-Size 16>]
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): 1 message sent from send queue
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): 1 message added to reception queue
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): 1 message acked by peer
[2020-04-07 19:53:32]: info: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): recv [L2TP tid=6233 sid=0 Ns=1 Nr=1 <Message-Type Start-Ctrl-Conn-Connected>]
[2020-04-07 19:53:32]: info: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): handling SCCCN
[2020-04-07 19:53:32]: error: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): impossible to connect tunnel: socket(AF_PPPOX) failed: Protocol not supported
[2020-04-07 19:53:32]: error: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): impossible to handle SCCCN: connecting tunnel failed, disconnecting tunnel
[2020-04-07 19:53:32]: info: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): sending StopCCN (res: 2, err: 0)
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): 1 message processed from reception queue
[2020-04-07 19:53:32]: info: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): send [L2TP tid=43765 sid=0 Ns=1 Nr=2 <Message-Type Stop-Ctrl-Conn-Notify> <Assigned-Tunnel-ID 6233> <Result-Code>]
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): 1 message sent from send queue
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): 1 message added to reception queue
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): 0 message acked by peer
[2020-04-07 19:53:32]: info: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): discarding message received while disconnecting
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): 1 message processed from reception queue
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): 0 message sent from send queue
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): sending ZLB
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): send [L2TP tid=43765 sid=0 Ns=2 Nr=3]
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): handling ZLB
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): recv [L2TP tid=6233 sid=0 Ns=3 Nr=2]
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): 0 message added to reception queue
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): 1 message acked by peer
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): 0 message processed from reception queue
[2020-04-07 19:53:32]: debug: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): 0 message sent from send queue
[2020-04-07 19:53:32]: info: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): tunnel disconnection acknowledged by peer, deleting tunnel
[2020-04-07 19:53:32]: info: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): deleting tunnel
[2020-04-07 19:53:32]: info: l2tp tunnel 6233-43765 (82.xx.xx.xx:39501): tunnel destroyed
My accel-ppp.conf
[ppp]
verbose=1
min-mtu=1180
mtu=1356
mru=1356
ccp=1
mppe=require
ipv4=require
ipv6=deny
ipv6-intf-id=0:0:0:1
ipv6-peer-intf-id=0:0:0:2
ipv6-accept-peer-intf-id=1


[l2tp]
bind=85.xx.xx.yy
verbose=1
dictionary=/usr/share/accel-ppp/l2tp/dictionary
hello-interval=300
host-name=domain.example.com
ip-pool=main_pool

[ip-pool]
gw-ip-address=85.xx.xx.yy
vendor=Cisco
attr=Cisco-AVPair
10.5.0.0/20,name=main_pool
and ipsec.conf
config setup
strictcrlpolicy=no
include /var/lib/strongswan/ipsec.conf.inc
virtual_private = %v4:10.0.0.0/8,%v4:192.168.0.0/16,%v4:172.16.0.0/12

conn %default
ikelifetime=60m
keylife=20m
rekeymargin=3m
keyingtries=3
authby=secret

conn l2tp
type=transport
pfs=no
rekey=no
left=85.xx.xx.yy
#left=%any
leftprotoport=17/1701
rightsubnetwithin=0.0.0.0/0
right=%any
rightprotoport=17/%any
dpdaction=clear
auto=add
ike=aes128-sha1-modp1536,aes128-sha1-modp1024,aes128-md5-modp1536,aes128-md5-modp1024,3des-sha1-modp1536,3des-sha1-modp1024,3des-md5-modp1536,3des-md5-modp1024
esp=aes128-sha1-modp1536,aes128-sha1-modp1024,aes128-md5-modp1536,aes128-md5-modp1024,3des-sha1-modp1536,3des-sha1-modp1024,3des-md5-modp1536,3des-md5-modp1024

conn l2tp_nat
rightsubnet=vhost:%priv
also=l2tp
What did I set up wrong?
PPTP and SSTP works fine.
dimka88
Posts: 866
Joined: 13 Oct 2014, 05:51
Contact:

Re: impossible to connect tunnel: socket(AF_PPPOX) failed: Protocol not supported

Post by dimka88 »

Hi, do you have kernel modules `l2tp_ppp` in your kernel?
Did you see any messages in `dmesg` when accel-ppp starting?
Can you check connection without ipsec?
edelwi
Posts: 2
Joined: 08 Apr 2020, 07:58

Re: impossible to connect tunnel: socket(AF_PPPOX) failed: Protocol not supported

Post by edelwi »

Thanks, of course not :roll: , i installed it:

Code: Select all

# dnf install kernel-modules-extra

# lsmod | grep l2tp_ppp
l2tp_ppp               28672  0
l2tp_netlink           28672  1 l2tp_ppp
l2tp_core              32768  2 l2tp_ppp,l2tp_netlink
pppox                  16384  2 l2tp_ppp,pptp
ppp_generic            45056  41 pppox,ppp_mppe,l2tp_ppp,ppp_async,pptp
and I was even able to connect successfully once (from ubuntu). I will restart accel-ppp later. Thanks again
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