Hello, I do have OpenVPN running on a VM, I would like to know how to restrict local network access from clients connecting the VPN. This is my nano /etc/openvpn/server/server.conf file: [code]################################################# # 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 # 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 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 dh none # 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 /var/log/openvpn/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" # 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" # 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 tls-crypt ta.key # Select a cryptographic cipher. # This config item must be copied to # the client config file as well. # Note that v2.4 client/server will automatically # negotiate AES-256-GCM in TLS mode. # See also the ncp-cipher option in the manpage ;cipher AES-256-CBC cipher AES-256-GCM auth SHA256 # Enable compression on the VPN link and push the # option to the client (v2.4+ only, for earlier # versions see below) ;compress lz4-v2 ;push "compress lz4-v2" # For compression compatible with older clients use comp-lzo # 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 /var/log/openvpn/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 /var/log/openvpn/openvpn.log ;log-append /var/log/openvpn/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 # Silence repeating messages. At most 20 # sequential messages of the same message # category will be output to the log. ;mute 20 # Notify the client that when the server restarts so it # can automatically reconnect. explicit-exit-notify 1[/code] Thanks. Guillaume

Any idea? I still need help. Thank-you in advance,

[quote=guillaumesoucy post_id=108478 time=1662829032 user_id=57955] I still need help [/quote][url=https://community.openvpn.net/openvpn/wiki/GettingHelp]Getting Help from Openvpn.[/url]

@TinCanTech Thanks for your reply. With respect, if I am posting here, it is because I did tried to fix it by myself at first. After spending several hours searching without finding the specific solution to my problem, I did post on this forum to get the exact solution. Best regards, Guillaume

Guillaume, can you elaborate on what you mean with "restricting access"? If you refer to preventing some clients from accessing some resources behind the server, then you would normally achieve this with a firewall. OpenVPN is not supposed to directly deal with this.

[quote=guillaumesoucy post_id=108481 time=1662831916 user_id=57955] I did post on this forum to get the exact solution [/quote]There is no such thing as [b][i]the exact solution[/i][/b] because it is different everywhere, dependent on local factors. [quote=guillaumesoucy post_id=108481 time=1662831916 user_id=57955] I did tried to fix it by myself at first [/quote]What did you [b][i]tried[/i][/b] so far ?

@ordex Yes, exactly what I mean, to preventing some clients from accessing some resources behind the VPN server. Example: I'm connected to VPN, and I do type in web browser 192.168.2.2, it will load the resource located at this IP as it is on the same gateway than the VPN server. In my case, 192.168.2.2 is one of the FreeNAS. I wish to be able to remove this ability. @TinCanTech I did tried several changed in the server.conf configuration file and also some tries at the firewall by following instructions here: https://serverfault.com/a/250948 It result of, I was still able to connect to the VPN server, local network access was blocked as I wish but the internet access as well. Please note that I'd took the time to adjust the syntax to match my current network setup. Concerning the firewall. is that something you guys can help me with on this forum or, this is considered out-of-scope help should be asked somewhere else? I red some tutorials concerning the firewall, I had some doubt than that could be what I should work on, however I'm not such of expert in firewalls. I want to avoid any mess. :-) Best regards, Guillaume

@ Guillaume The reason that nobody responded to your original post is because you provided [b]absolute zero[/b] details.

@TinCanTech Knowing that we confirm that it's actually a firewall thing, is this forums could be a suitable place to pursue the troubleshoot? Warm regards, Guillaume

Personally, I firmly believe that [b]freedom of speech[/b] is a [b]human right[/b]. Which applies to [i]everybody[/i].

I'm agreeing with you. So if you or any body can help me with the next steps I will be more than happy. ;-)

How to prevent clients from accessing other machines on the network.

harsh9605

I guess this link can help you :- https://openvpn.net/community-resources/configuring-client-specific-rules-and-access-policies/

harsh9605

I guess this link can help you :- https://openvpn.net/community-resources/configuring-client-specific-rules-and-access-policies/

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