Can't connect over WiFi

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fede
OpenVpn Newbie
Posts: 4
Joined: Wed Jun 17, 2015 5:52 am

Can't connect over WiFi

Post by fede » Wed Jun 17, 2015 6:09 am

Hi all, first post here, not sure if this is the right place for my question.

I've got my open vpn server correctly configured and working at home in a raspberry pi. I can connect to it without any problems from my android phone when I'm on the 3G but now what I'm trying to achieve is to be able to connect also using the WiFi at work. My suspicious is that some sort of blocking is going on at my work's wifi but not entirely sure what could it be and how to bypass it.
Even when I'm pretty sure that my openvpn isn't the problem (the problem it's just with this network), I've changed my server settings to listen on tcp 443 with the hope that that will maybe avoid filtering or whatever causing the TLS handshake to succeed, but no luck, I got the same result

So, basically the connection it's established, but then it fails during the TLS negotiation phaseJun 17 15:49:31 raspbx ovpn-server[4447]: TCP/UDP: Closing socket

Code: Select all

Jun 17 15:49:38 raspbx ovpn-server[4447]: MULTI: multi_create_instance called
Jun 17 15:49:38 raspbx ovpn-server[4447]: Re-using SSL/TLS context
Jun 17 15:49:38 raspbx ovpn-server[4447]: LZO compression initialized
Jun 17 15:49:38 raspbx ovpn-server[4447]: Control Channel MTU parms [ L:1560 D:168 EF:68 EB:0 ET:0 EL:0 ]
Jun 17 15:49:38 raspbx ovpn-server[4447]: Data Channel MTU parms [ L:1560 D:1450 EF:60 EB:135 ET:0 EL:0 AF:3/1 ]
Jun 17 15:49:38 raspbx ovpn-server[4447]: Local Options String: 'V4,dev-type tun,link-mtu 1560,tun-mtu 1500,proto TCPv4_SERVER,comp-lzo,keydir 0,cipher AES-256-CBC,auth SHA1,keysize 256,tls-auth,key-method 2,tls-server'
Jun 17 15:49:38 raspbx ovpn-server[4447]: Expected Remote Options String: 'V4,dev-type tun,link-mtu 1560,tun-mtu 1500,proto TCPv4_CLIENT,comp-lzo,keydir 1,cipher AES-256-CBC,auth SHA1,keysize 256,tls-auth,key-method 2,tls-client'
Jun 17 15:49:38 raspbx ovpn-server[4447]: Local Options hash (VER=V4): '9915e4a2'
Jun 17 15:49:38 raspbx ovpn-server[4447]: Expected Remote Options hash (VER=V4): '2f2c6498'
Jun 17 15:49:38 raspbx ovpn-server[4447]: TCP connection established with [AF_INET]xxx.xxx.xxx.x:42026
Jun 17 15:49:38 raspbx ovpn-server[4447]: TCPv4_SERVER link local: [undef]
Jun 17 15:49:38 raspbx ovpn-server[4447]: TCPv4_SERVER link remote: [AF_INET]xxx.xxx.xxx.x:42026
Jun 17 15:49:39 raspbx ovpn-server[4447]: xxx.xxx.xxx.x:42026 TLS: Initial packet from [AF_INET]218.185.233.6:42026, sid=35b998e5 20f78939
Jun 17 15:50:38 raspbx ovpn-server[4447]: xxx.xxx.xxx.x:42026 TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity)
Jun 17 15:50:38 raspbx ovpn-server[4447]: xxx.xxx.xxx.x:42026 TLS Error: TLS handshake failed
Jun 17 15:50:38 raspbx ovpn-server[4447]: xxx.xxx.xxx.x:42026 Fatal TLS error (check_tls_errors_co), restarting
Jun 17 15:50:38 raspbx ovpn-server[4447]: xxx.xxx.xxx.x:42026 SIGUSR1[soft,tls-error] received, client-instance restarting
Jun 17 15:50:38 raspbx ovpn-server[4447]: TCP/UDP: Closing socket
Any help, would be greatly appreciated!

User avatar
Traffic
OpenVPN Protagonist
Posts: 4066
Joined: Sat Aug 09, 2014 11:24 am

Re: Can't connect over WiFi

Post by Traffic » Wed Jun 17, 2015 9:26 pm

fede wrote:Jun 17 15:49:39 raspbx ovpn-server[4447]: xxx.xxx.xxx.x:42026 TLS: Initial packet from [AF_INET]218.185.233.6:42026, sid=35b998e5 20f78939
Jun 17 15:50:38 raspbx ovpn-server[4447]: xxx.xxx.xxx.x:42026 TLS Error: TLS key negotiation failed to occur within 60 seconds (check your network connectivity)
Jun 17 15:50:38 raspbx ovpn-server[4447]: xxx.xxx.xxx.x:42026 TLS Error: TLS handshake failed
Jun 17 15:50:38 raspbx ovpn-server[4447]: xxx.xxx.xxx.x:42026 Fatal TLS error (check_tls_errors_co), restarting
I found this in the source:

forward.c:

Code: Select all

void
check_tls_errors_co (struct context *c)
{
  msg (D_STREAM_ERRORS, "Fatal TLS error (check_tls_errors_co), restarting");
  register_signal (c, c->c2.tls_exit_signal, "tls-error"); /* SOFT-SIGUSR1 -- TLS error */
}
but I cannot decode its meaning.

Please post your configs for further help.

Also, include full details of openvpn server and client version and OS.

fede
OpenVpn Newbie
Posts: 4
Joined: Wed Jun 17, 2015 5:52 am

Re: Can't connect over WiFi

Post by fede » Thu Jun 18, 2015 12:54 am

Hi Traffic, thanks heaps for your help!

Server it's running on a raspberry pi, with Linux raspbx 3.6.11+ armv6l GNU/Linux (debian based) with OpenVPN Server Version: 2.2.1-8+deb7u3
Client is using openvpn version 2.4 and it's running on a Nexus 4 with the latest Android (v5.1.1) and OpenVPN for Android version 0.6.30

Please find below the server and client configs (noticed I've removed the certificates):

Code: Select all

cat /etc/openvpn/server.conf 
#################################################
# Sample OpenVPN 2.0 config file for            #
# multi-client server.                          #
#                                               #
# This file is for the server side              #
# of a many-clients <-> one-server              #
# OpenVPN configuration.                        #
#                                               #
# OpenVPN also supports                         #
# single-machine <-> single-machine             #
# configurations (See the Examples page         #
# on the web site for more info).               #
#                                               #
# This config should work on Windows            #
# or Linux/BSD systems.  Remember on            #
# Windows to quote pathnames and use            #
# double backslashes, e.g.:                     #
# "C:\\Program Files\\OpenVPN\\config\\foo.key" #
#                                               #
# Comments are preceded with '#' or ';'         #
#################################################

# Which local IP address should OpenVPN
# listen on? (optional)
;local a.b.c.d

# Which TCP/UDP port should OpenVPN listen on?
# If you want to run multiple OpenVPN instances
# on the same machine, use a different port
# number for each one.  You will need to
# open up this port on your firewall.
#port 1199
port 443

# TCP or UDP server?
proto tcp
;proto udp

# "dev tun" will create a routed IP tunnel,
# "dev tap" will create an ethernet tunnel.
# Use "dev tap0" if you are ethernet bridging
# and have precreated a tap0 virtual interface
# and bridged it with your ethernet interface.
# If you want to control access policies
# over the VPN, you must create firewall
# rules for the the TUN/TAP interface.
# On non-Windows systems, you can give
# an explicit unit number, such as tun0.
# On Windows, use "dev-node" for this.
# On most systems, the VPN will not function
# unless you partially or fully disable
# the firewall for the TUN/TAP interface.
;dev tap
dev tun

# Windows needs the TAP-Win32 adapter name
# from the Network Connections panel if you
# have more than one.  On XP SP2 or higher,
# you may need to selectively disable the
# Windows firewall for the TAP adapter.
# Non-Windows systems usually don't need this.
;dev-node MyTap

# SSL/TLS root certificate (ca), certificate
# (cert), and private key (key).  Each client
# and the server must have their own cert and
# key file.  The server and all clients will
# use the same ca file.
#
# See the "easy-rsa" directory for a series
# of scripts for generating RSA certificates
# and private keys.  Remember to use
# a unique Common Name for the server
# and each of the client certificates.
#
# Any X509 key management system can be used.
# OpenVPN can also use a PKCS #12 formatted key file
# (see "pkcs12" directive in man page).
ca /etc/openvpn/easy-rsa/easyrsa3/pki/ca.crt
cert /etc/openvpn/easy-rsa/easyrsa3/pki/issued/server.crt
key /etc/openvpn/easy-rsa/easyrsa3/pki/private/server.key  # This file should be kept secret

# Diffie hellman parameters.
# Generate your own with:
#   openssl dhparam -out dh1024.pem 1024
# Substitute 2048 for 1024 if you are using
# 2048 bit keys. 
dh /etc/openvpn/easy-rsa/easyrsa3/pki/dh.pem

# Configure server mode and supply a VPN subnet
# for OpenVPN to draw client addresses from.
# The server will take 10.8.0.1 for itself,
# the rest will be made available to clients.
# Each client will be able to reach the server
# on 10.8.0.1. Comment this line out if you are
# ethernet bridging. See the man page for more info.
server 10.88.99.0 255.255.255.0

# Maintain a record of client <-> virtual IP address
# associations in this file.  If OpenVPN goes down or
# is restarted, reconnecting clients can be assigned
# the same virtual IP address from the pool that was
# previously assigned.
ifconfig-pool-persist ipp.txt

# Configure server mode for ethernet bridging.
# You must first use your OS's bridging capability
# to bridge the TAP interface with the ethernet
# NIC interface.  Then you must manually set the
# IP/netmask on the bridge interface, here we
# assume 10.8.0.4/255.255.255.0.  Finally we
# must set aside an IP range in this subnet
# (start=10.8.0.50 end=10.8.0.100) to allocate
# to connecting clients.  Leave this line commented
# out unless you are ethernet bridging.
;server-bridge 10.8.0.4 255.255.255.0 10.8.0.50 10.8.0.100

# Configure server mode for ethernet bridging
# using a DHCP-proxy, where clients talk
# to the OpenVPN server-side DHCP server
# to receive their IP address allocation
# and DNS server addresses.  You must first use
# your OS's bridging capability to bridge the TAP
# interface with the ethernet NIC interface.
# Note: this mode only works on clients (such as
# Windows), where the client-side TAP adapter is
# bound to a DHCP client.
;server-bridge

# Push routes to the client to allow it
# to reach other private subnets behind
# the server.  Remember that these
# private subnets will also need
# to know to route the OpenVPN client
# address pool (10.8.0.0/255.255.255.0)
# back to the OpenVPN server.
;push "route 192.168.10.0 255.255.255.0"
;push "route 192.168.20.0 255.255.255.0"
;push "route 10.0.0.0 255.255.255.0"

# To assign specific IP addresses to specific
# clients or if a connecting client has a private
# subnet behind it that should also have VPN access,
# use the subdirectory "ccd" for client-specific
# configuration files (see man page for more info).

# EXAMPLE: Suppose the client
# having the certificate common name "Thelonious"
# also has a small subnet behind his connecting
# machine, such as 192.168.40.128/255.255.255.248.
# First, uncomment out these lines:
;client-config-dir ccd
;route 192.168.40.128 255.255.255.248
# Then create a file ccd/Thelonious with this line:
#   iroute 192.168.40.128 255.255.255.248
# This will allow Thelonious' private subnet to
# access the VPN.  This example will only work
# if you are routing, not bridging, i.e. you are
# using "dev tun" and "server" directives.

# EXAMPLE: Suppose you want to give
# Thelonious a fixed VPN IP address of 10.9.0.1.
# First uncomment out these lines:
;client-config-dir ccd
;route 10.9.0.0 255.255.255.252
# Then add this line to ccd/Thelonious:
#   ifconfig-push 10.9.0.1 10.9.0.2

# Suppose that you want to enable different
# firewall access policies for different groups
# of clients.  There are two methods:
# (1) Run multiple OpenVPN daemons, one for each
#     group, and firewall the TUN/TAP interface
#     for each group/daemon appropriately.
# (2) (Advanced) Create a script to dynamically
#     modify the firewall in response to access
#     from different clients.  See man
#     page for more info on learn-address script.
;learn-address ./script

# If enabled, this directive will configure
# all clients to redirect their default
# network gateway through the VPN, causing
# all IP traffic such as web browsing and
# and DNS lookups to go through the VPN
# (The OpenVPN server machine may need to NAT
# or bridge the TUN/TAP interface to the internet
# in order for this to work properly).
push "redirect-gateway def1 bypass-dhcp"

# Certain Windows-specific network settings
# can be pushed to clients, such as DNS
# or WINS server addresses.  CAVEAT:
# http://openvpn.net/faq.html#dhcpcaveats
# The addresses below refer to the public
# DNS servers provided by opendns.com.
;push "dhcp-option DNS 208.67.222.222"
;push "dhcp-option DNS 208.67.220.220"
push "dhcp-option DNS 10.88.99.1"

# Uncomment this directive to allow different
# clients to be able to "see" each other.
# By default, clients will only see the server.
# To force clients to only see the server, you
# will also need to appropriately firewall the
# server's TUN/TAP interface.
client-to-client

# Uncomment this directive if multiple clients
# might connect with the same certificate/key
# files or common names.  This is recommended
# only for testing purposes.  For production use,
# each client should have its own certificate/key
# pair.
#
# IF YOU HAVE NOT GENERATED INDIVIDUAL
# CERTIFICATE/KEY PAIRS FOR EACH CLIENT,
# EACH HAVING ITS OWN UNIQUE "COMMON NAME",
# UNCOMMENT THIS LINE OUT.
;duplicate-cn

# The keepalive directive causes ping-like
# messages to be sent back and forth over
# the link so that each side knows when
# the other side has gone down.
# Ping every 10 seconds, assume that remote
# peer is down if no ping received during
# a 120 second time period.
keepalive 10 120

# For extra security beyond that provided
# by SSL/TLS, create an "HMAC firewall"
# to help block DoS attacks and UDP port flooding.
#
# Generate with:
#   openvpn --genkey --secret ta.key
#
# The server and each client must have
# a copy of this key.
# The second parameter should be '0'
# on the server and '1' on the clients.
tls-auth /etc/openvpn/easy-rsa/easyrsa3/pki/ta.key 0 # This file is secret

# Select a cryptographic cipher.
# This config item must be copied to
# the client config file as well.
;cipher BF-CBC        # Blowfish (default)
;cipher AES-128-CBC   # AES
;cipher DES-EDE3-CBC  # Triple-DES
cipher AES-256-CBC # Added by FedeX

# Enable compression on the VPN link.
# If you enable it here, you must also
# enable it in the client config file.
comp-lzo

# The maximum number of concurrently connected
# clients we want to allow.
;max-clients 100

# It's a good idea to reduce the OpenVPN
# daemon's privileges after initialization.
#
# You can uncomment this out on
# non-Windows systems.
user nobody
group nogroup

# The persist options will try to avoid
# accessing certain resources on restart
# that may no longer be accessible because
# of the privilege downgrade.
persist-key
persist-tun

# Output a short status file showing
# current connections, truncated
# and rewritten every minute.
status openvpn-status.log

# By default, log messages will go to the syslog (or
# on Windows, if running as a service, they will go to
# the "\Program Files\OpenVPN\log" directory).
# Use log or log-append to override this default.
# "log" will truncate the log file on OpenVPN startup,
# while "log-append" will append to it.  Use one
# or the other (but not both).
;log         openvpn.log
;log-append  openvpn.log

# Set the appropriate level of log
# file verbosity.
#
# 0 is silent, except for fatal errors
# 4 is reasonable for general usage
# 5 and 6 can help to debug connection problems
# 9 is extremely verbose
;verb 3
verb 5

# Silence repeating messages.  At most 20
# sequential messages of the same message
# category will be output to the log.
;mute 20

Code: Select all

# Enables connection to GUI
management /data/data/de.blinkt.openvpn/cache/mgmtsocket unix
management-client
management-query-passwords
management-hold

setenv IV_GUI_VER "de.blinkt.openvpn 0.6.29"
machine-readable-output
ifconfig-nowarn
client
verb 4
connect-retry-max 5
connect-retry 5
resolv-retry 60
dev tun
remote yyy.xxx.zzz 443 tcp-client
<ca>
-----BEGIN CERTIFICATE-----

-----END CERTIFICATE-----

</ca>
<key>
-----BEGIN PRIVATE KEY-----

-----END PRIVATE KEY-----

</key>
<cert>
Certificate:
Data:
Version: 3 (0x2)
Serial Number: 2 (0x2)
Signature Algorithm: sha256WithRSAEncryption
Issuer: CN=RasPBX
Validity
Not Before: Nov 28 08:40:30 2013 GMT
Not After : Nov 26 08:40:30 2023 GMT
Subject: CN=client1
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
Public-Key: (2048 bit)
Modulus:

Exponent: 65537 (0x10001)
X509v3 extensions:
X509v3 Basic Constraints:
CA:FALSE
X509v3 Subject Key Identifier:
63:
X509v3 Authority Key Identifier:
keyid:85:
DirName:/CN=RasPBX
serial:C6:

X509v3 Extended Key Usage:
TLS Web Client Authentication
X509v3 Key Usage:
Digital Signature
Signature Algorithm: sha256WithRSAEncryption

-----BEGIN CERTIFICATE-----


-----END CERTIFICATE-----

</cert>
comp-lzo
<tls-auth>
#
# 2048 bit OpenVPN static key
#
-----BEGIN OpenVPN Static key V1-----

-----END OpenVPN Static key V1-----

</tls-auth>
key-direction 1
route 0.0.0.0 0.0.0.0 vpn_gateway
dhcp-option DNS 10.0.0.1
dhcp-option DNS 8.8.4.4
dhcp-option DOMAIN blinkt.de
verify-x509-name server name
cipher AES-256-CBC
# Use system proxy setting
management-query-proxy

So this settings, work fine in any network (ie: 3G) but my work's :(

Thanks
Fede

fede
OpenVpn Newbie
Posts: 4
Joined: Wed Jun 17, 2015 5:52 am

Re: Can't connect over WiFi

Post by fede » Thu Jun 18, 2015 1:02 am

Almost forgot, I've also tried adding option "hand-window 120" on both sides but that didn't help, as I got the same error but instead of 60 secs waited for 120 secs:

Code: Select all

Jun 18 10:40:29 raspbx ovpn-server[5854]: xxx.xxx.xxx.x:63485 TLS Error: TLS key negotiation failed to occur within 120 seconds (check your network connectivity)
Jun 18 10:40:29 raspbx ovpn-server[5854]: xxx.xxx.xxx.x:63485 TLS Error: TLS handshake failed
Jun 18 10:40:29 raspbx ovpn-server[5854]: xxx.xxx.xxx.x:63485 Fatal TLS error (check_tls_errors_co), restarting
Jun 18 10:40:29 raspbx ovpn-server[5854]: xxx.xxx.xxx.x:63485 SIGUSR1[soft,tls-error] received, client-instance restarting
Jun 18 10:40:29 raspbx ovpn-server[5854]: TCP/UDP: Closing socket
Thanks again!

User avatar
Traffic
OpenVPN Protagonist
Posts: 4066
Joined: Sat Aug 09, 2014 11:24 am

Re: Can't connect over WiFi

Post by Traffic » Thu Jun 18, 2015 3:58 pm

fede wrote:Please find below the server and client configs (noticed I've removed the certificates):
Shame you did not remove all the useless cruft (comments etc) ...
fede wrote:this settings, work fine in any network (ie: 3G) but my work's
IE: the only place this setup does not work is when your client is located inside your work's network.

Best place to ask .. your work's network admin.
Perhaps they block you deliberately ..

fede
OpenVpn Newbie
Posts: 4
Joined: Wed Jun 17, 2015 5:52 am

Re: Can't connect over WiFi

Post by fede » Thu Jun 18, 2015 11:06 pm

Shame you did not remove all the useless cruft (comments etc) ...
Ops...my bad sorry about that, couldn't find a way to edit the post
IE: the only place this setup does not work is when your client is located inside your work's network.
Yup, that's what I said
Best place to ask .. your work's network admin.
Perhaps they block you deliberately ..
I can't since we aren't allowed to, that's why my original question clearly says:
My suspicious is that some sort of blocking is going on at my work's wifi but not entirely sure what could it be and how to bypass it.
Thanks

md123
OpenVpn Newbie
Posts: 2
Joined: Thu Oct 13, 2016 11:12 pm

Re: Can't connect over WiFi

Post by md123 » Thu Oct 13, 2016 11:23 pm

Check your BIOS. I posted an answer on another thread because the symptoms are very hard to troubleshoot. You're tripped into thinking it's openvpn, when in fact its your bios that allows windows to disable your wifi when there's another LAN connection - which happens as soon as you connect to the vpn server.

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