Connecting 2 Clients to Server and accessing the network behind these clients

[DateMike]

Hi Guys,

Basically, I have a CentOS 6 Hosted Server, it is running a piece of software that monitors devices via SNMP.
I have two branches that are remote to where the server is hosted and hence have created a VPN between these two branches to get them to talk to the server.
- I have installed OVPN on my server - All good.
- I installed OVPN client on to a Mikrotik Router (Mikrotik A) and connected the router to the server via VPN - All good
- I created a route on my CentOS server to search for the Network beyond Mikrotik A and was able to find the network and devices on the network - All good. (The network behind the router is 10.0.0.0/24)
- I installed OVPN on to the second Mikrotik Router (Mikrotik B) and connected to the server via VPN - All good.
- I created a route on my CentOS server to search for the Network beyond Mikrotik B and was not able to find the network and devices on the network - Not All good (The network behind the router is 10.0.1.0/24)

Any ideas on what to do here so I can view the devices on both networks and in the future, more networks.

Thanks,

[TinCanTech]

Please see:
HOWTO: Request Help !

HOWTO: Expanding the scope of the VPN to include additional machines

[DateMike]

Hi, Please see below post for config files, apologies for the incorrect 1st post:

Server Configuration File on CentOS6 v openvpn-2.3.12-1.e16.x86_64

View OriginalSERVER

#################################################
# 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 1194
port 443
# TCP or UDP server?
proto tcp-server
;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 ca.crt
cert server.crt
key server.key # This file should be kept secret

# Diffie hellman parameters.
# Generate your own with:
# openssl dhparam -out dh2048.pem 2048
dh dh2048.pem

# Network topology
# Should be subnet (addressing via IP)
# unless Windows clients v2.0.9 and lower have to
# be supported (then net30, i.e. a /30 per client)
# Defaults to net30 (not recommended)
topology subnet

# 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 10.8.0.0 255.255.255.0

# 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 192.168.1.0 255.255.255.0"

# 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 a.b.c.d 255.255.255.0
route e.f.g.h 255.255.255.0
# 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 10.2.0.0 255.255.255.0
route 10.1.0.0 255.255.255.0
# 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 8.8.8.8"
push "dhcp-option DNS 8.8.4.4"

# 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 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

# 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 nobody

# 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 4

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

Server Log:

Code: Select all

OpenVPN CLIENT LIST
Updated,Tue Dec  6 11:50:43 2016
Common Name,Real Address,Bytes Received,Bytes Sent,Connected Since
VPN1,Real address 1,9969,9368,Tue Dec  6 11:43:43 2016
VPN2,Real address 2,7445,7240,Tue Dec  6 11:43:42 2016
ROUTING TABLE
Virtual Address,Common Name,Real Address,Last Ref
a.b.c.d/24,VPN1,Real Address 1,Tue Dec  6 11:43:45 2016
10.1.0.1,VPN1,Real address 1,Tue Dec  6 11:50:33 2016
10.2.0.1,VPN2,Real address 2,Tue Dec  6 11:49:57 2016
e.f.g.h/24,VPN2,Real address 2,Tue Dec  6 11:43:44 2016
GLOBAL STATS
Max bcast/mcast queue length,0
END

VPN1 Client Info (comes from Mikrotik RB951G-2HnD terminal)

View OriginalCLIENT

Flags: X - disabled, R - running
0 R name="myvpn1" mac-address=MACADDRESS max-mtu=1500
connect-to=x.x.x.x port=443 mode=ip user="vpnuser"
password="vpnpass" profile=OVPN-Client certificate=VPN1 auth=sha1
cipher=blowfish128 add-default-route=no

VPN2 Client Info (comes from Mikrotik RB951G-2HnD terminal)

View OriginalCLIENT

Flags: X - disabled, R - running
0 R name="myvpn2" mac-address=MAC ADDRESS max-mtu=1500
connect-to=x.x.x.x port=443 mode=ip user="vpnuser"
password="vpnpass" profile=OVPN-client certificate=VPN2 auth=sha1
cipher=blowfish128 add-default-route=no

Not sure how to get Client logs from Mikrotik Router.

I would like to access the devices behind both the VPN1 and VPN2 routers.
I have added two files to the /ccd directory containing the following:
VPN1 ccd file

Code: Select all

ifconfig-push 10.1.0.1 10.1.0.2
iroute a.b.c.d 255.255.255.0

VPN2 ccd file

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ifconfig-push 10.2.0.1 10.2.0.2
iroute e.f.g.h 255.255.255.0

Route table created by ovpn on CentOS server

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10.2.0.0/24 via 10.8.0.2 dev tun0
a.b.c.d/24 via 10.8.0.2 dev tun0
e.f.g.h/24 via 10.8.0.2 dev tun0
10.8.0.0/24 dev tun0  proto kernel  scope link  src 10.8.0.1
10.1.0.0/24 via 10.8.0.2 dev tun0

I am able to ping a device on the a.b.c.d network via my CentOS server but unable to ping a device on the e.f.g.h network.

regards,

[TinCanTech]

I created a route on my CentOS server to search for the Network beyond Mikrotik B and was not able to find the network and devices on the network - Not All good (The network behind the router is 10.0.1.0/24)

I have added two files to the /ccd directory containing the following:
VPN1 ccd file

Code: Select all
ifconfig-push 10.1.0.1 10.1.0.2
iroute a.b.c.d 255.255.255.0

VPN2 ccd file

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ifconfig-push 10.2.0.1 10.2.0.2
iroute e.f.g.h 255.255.255.0

I presume the network in question is e.f.g.h ?

Is the Mikrotik Router the default gateway for the client LAN ?

[DateMike]

Hi TinCan,

Yea, trying to access the devices on the e.f.g.h network.

The Mikrotik router is not the default gateway for either of the client LANs.

They are connected to a normal ISP router which is the default gateway for each LAN.

[TinCanTech]

The client LAN machines need a route for the VPN.

[DateMike]

So do I add a route on the Mikrotik router for e.f.g.h through 10.2.0.1?

[DateMike]

What I don't get is how I can access the a.b.c.d network and using the exact same setup can't access the e.f.g.h network...

[TinCanTech]

Probably, because your client networks are not configured in the same way.

[DateMike]

But the only difference in the two networks is one is a.b.c.d and the other is e.f.g.h

[TinCanTech]

The only difference you are aware of ..

Can you ping from the server to the LAN IP of Mikrotik B router ?

[DateMike]

I can ping the LAN IP of the Mikrotik B router

[TinCanTech]

The client LAN machines need a route for the VPN.

They all need a route.