lost connection to remote client

bernd67

hello forum,

i have a problem with a connection from a win10 pro client to another remote win 10 pro machine using rdp and openvpn.
all was fine earlier..but last weeks connecition freezes..

i used openvpn version
2.4.7 ....done clean install with 2.4.8 i602 win 10...on client and remote machine

************
config files where saved...

client:
remote x.ddns.net
dev tun
ifconfig 10.0.0.2 10.0.0.1
secret key.txt
port 5...

cipher AES-256-CBC

*************

...checked vpn log.. found: Message:

...ciphers have a block size of less than.. so checked google, told me to put into config file a line with:

cipher AES-256-CBC .. done that way!

and:
disabling NCP mode (--ncp-disable) because not in P2MP client or server mode

but now i have no! rdp connection any more.. not starting up.. even if i remove cipher from config.

Fri Jan 03 14:13:16 2020 TCP/UDP: Preserving recently used remote address: [AF_INET]87...:5...
Fri Jan 03 14:13:16 2020 UDP link local (bound): [AF_INET][undef]:5...
Fri Jan 03 14:13:16 2020 UDP link remote: [AF_INET]87.....:5...
Fri Jan 03 14:13:33 2020 Authenticate/Decrypt packet error: cipher final failed

TinCanTech

If you change the client you must also change the server config accordingly ...

bernd67

was done, i know..
on server/remote client config is:

dev tun
ifconfig 10.0.0.1 10.0.0.2
secret key.txt
port 5...
cipher AES-256-CBC

still not able to get a rdp session which worked till today, ok the last weeks with freeze sometimes but ..

bernd67

Log auf Remote Client/Server:
Fri Jan 03 17:09:34 2020 disabling NCP mode (--ncp-disable) because not in P2MP client or server mode !!!
Fri Jan 03 17:09:34 2020 OpenVPN 2.4.8 x86_64-w64-mingw32 [SSL (OpenSSL)] [LZO] [LZ4] [PKCS11] [AEAD] built on Oct 31 2019
Fri Jan 03 17:09:34 2020 Windows version 6.2 (Windows 8 or greater) 64bit
Fri Jan 03 17:09:34 2020 library versions: OpenSSL 1.1.0l 10 Sep 2019, LZO 2.10
Fri Jan 03 17:09:34 2020 open_tun
Fri Jan 03 17:09:34 2020 TAP-WIN32 device [LAN-Verbindung 2] opened: \\.\Global\{7......tap
Fri Jan 03 17:09:34 2020 Notified TAP-Windows driver to set a DHCP IP/netmask of 10.0.0.1/255.255.255.252 on interface {7......} [DHCP-serv: 10.0.0.2, lease-time: 31...]
Fri Jan 03 17:09:34 2020 Successful ARP Flush on interface [8] {7....}
Fri Jan 03 17:09:34 2020 Could not determine IPv4/IPv6 protocol. Using AF_INET6 !!!!!!!
Fri Jan 03 17:09:34 2020 setsockopt(IPV6_V6ONLY=0)
Fri Jan 03 17:09:34 2020 UDPv6 link local (bound): [AF_INET6][undef]:5..
Fri Jan 03 17:09:34 2020 UDPv6 link remote: [AF_UNSPEC]

means that that no connection was built up , no vpn tunnel?

bernd67

First of all now:
Thx a lot TinCan! for support or answer to me and try to help in my case!

on client i get now:
Fri Jan 03 17:14:30 2020 Initialization Sequence Completed
after restart of connection..
and rdp connection up and running again!
great, but no idea why its working now.

still open or additional questions now:

how can i automate the start of openvpn on startup of machines?
how can i configure a message to mobile or email if there is a trouble with the connection?

Fri Jan 03 17:09:34 2020 Could not determine IPv4/IPv6 protocol. Using AF_INET still message..

Fri Jan 03 17:14:19 2020 disabling NCP mode (--ncp-disable) because not in P2MP client or server mode
what exactly does that mean, and how to configure it to disapear?

in rdp session now the problem i do not see the cursor... maybe after a restart..? but can start programs etc..

TinCanTech

bernd67 wrote disabling NCP mode (--ncp-disable) because not in P2MP client or server mode
what exactly does that mean, and how to configure it to disapear?

You are running openvpn in P2P mode.

Please start with the Howto:
https://community.openvpn.net/openvpn/wiki/HOWTO

bernd67

'Thx TinCanTech!

ok, learned Openvpn is running as service under Windows and started automatically...
https://community.openvpn.net/openvpn/wiki/HOWTO#Windows

"You are running openvpn in P2P mode.":
https://community.openvpn.net/openvpn/wiki/Topology
This topology uses Point-to-Point networking. This is not compatible with Windows clients, though use with non-Windows allows use of the entire subnet (no "lost" IPs.)

-->>I added "--ncp-disable" line to config

-->> only warning left: WARNING: this configuration may cache passwords in memory -- use the auth-nocache
set to config: "auth-nocache"

No Errors according to logfile any more!
Logfile ends with: "Initialization Sequence Completed"

BUT:
still the problem that since i changed all the openvpn settings and upgraded to 2.4.8 windows 10 openvpn version i get error:
Cursor not to be seen in rdp connection window, only in the small blue part on top of rdp window.

cursor to be seen in logon process till login and after login only in the little square blue window in top middle... where the openvpn ip is displayed.
but keyboard input is ok for desktop acitivity... any info to this strange thing?

google does display some similar things but does not offer a real help.

TinCanTech

Openvpn tunnel is working, although, I would recommend you use a server/client tunnel not PTP.

As for RDP, sorry we don't support MS RDP here.

If all else fails you can contact me privately: tincanteksup <at> gmail
(Fees apply)