Manual:Interface/OVPN

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Applies to RadioOS: v5+


Summary

Standards:
Package: ppp


Currently unsupported OVPN feature:

  • UDP mode
  • LZO compression
  • TLS authentication
  • authentication without username/password

OVPN Client

Sub-menu: /interface ovpn-client

Properties

Property Description
add-default-route (yes | no; Default: no) Whether to add OVPN remote address as a default route.
auth (md5 | sha1; Default: sha1) Allowed authentication methods.
certificate (string | none; Default: none) Name of the client certificate imported into certificate list.
cipher (aes128 | aes192 | aes256 | blowfish128; Default: blowfish128) Allowed ciphers.
comment (string; Default: ) Descriptive name of an item
connect-to (IP; Default: ) Remote address of the OVPN server.
disabled (yes | no; Default: yes) Whether interface is disabled or not. By default it is disabled.
mac-address (MAC; Default: ) Mac address of OVPN interface. Will be auto generated if not specified.
max-mtu (integer; Default: 1500) Maximum Transmission Unit. Max packet size that OVPN interface will be able to send without packet fragmentation.
mode (ip | ethernet; Default: ip) Layer3 or layer2 tunnel mode (alternatively tun, tap)
name (string; Default: ) Descriptive name of the interface.
password (string; Default: "") Password used for authentication.
port (integer; Default: 1194) Port to connect to.
profile (name; Default: default) Used PPP profile.
user (string; Default: ) User name used for authentication.

Quick example

This example demonstrates how to set up OVPN client with username "test", password "123" and server 10.1.101.1


[admin@bumba] /interface ovpn-client> add connect-to=10.1.101.1 user=test password=123 disabled=no 
[admin@bumba] /interface ovpn-client> print 
Flags: X - disabled, R - running 
 0    name="ovpn-out1" mac-address=FE:7B:9C:F9:59:D0 max-mtu=1500 connect-to=10.1.101.1 
      port=1194 mode=ip user="test" password="123" profile=default certificate=none auth=sha1 
      cipher=blowfish128 add-default-route=no 

OVPN Server

Sub-menu: /interface ovpn-server


This sub-menu shows interfaces for each connected OVPN clients.

An interface is created for each tunnel established to the given server. There are two types of interfaces in OVPN server's configuration

  • Static interfaces are added administratively if there is a need to reference the particular interface name (in firewall rules or elsewhere) created for the particular user.
  • Dynamic interfaces are added to this list automatically whenever a user is connected and its username does not match any existing static entry (or in case the entry is active already, as there can not be two separate tunnel interfaces referenced by the same name).

Dynamic interfaces appear when a user connects and disappear once the user disconnects, so it is impossible to reference the tunnel created for that use in router configuration (for example, in firewall), so if you need a persistent rule for that user, create a static entry for him/her. Otherwise it is safe to use dynamic configuration.


Icon-note.png

Note: in both cases PPP users must be configured properly - static entries do not replace PPP configuration.



Server configuration

Sub-menu: /interface ovpn-server server


Properties:

Property Description
auth (sha1 | md5; Default: sha1,md5) Authentication methods that server will accept.
certificate (name | none; Default: none) Name of the certificate that OVPN server will use.
cipher (aes128 | aes192 | aes256 | blowfish128; Default: aes128,blowfish128) Allowed ciphers.
default-profile (name; Default: default) Default profile to use.
enabled (yes | no; Default: no) Defines whether OVPN server is enabled or not.
keepalive-timeout (integer | disabled; Default: 60) Defines the time period (in seconds) after which the router is starting to send keepalive packets every second. If no traffic and no keepalive responses has came for that period of time (i.e. 2 * keepalive-timeout), not responding client is proclaimed disconnected
mac-address (MAC; Default: ) Auto Generated MAC address of the server.
max-mtu (integer; Default: 1500) Maximum Transmission Unit. Max packet size that OVPN interface will be able to send without packet fragmentation.
mode (ip | ethernet; Default: ip) Layer3 or layer2 tunnel mode (alternatively tun, tap)
netmask (integer; Default: 24) Subnet mask to be applied to client.
port (integer; Default: 1194) Port to run server on.
require-client-certificate (yes | no; Default: no) If set to yes, then server checks whether client's certificate belongs to the same certificate chain.


[admin@bumba] /interface ovpn-server server set enabled=yes 
[admin@bumba] /interface ovpn-server server set certificate=server 
[admin@bumba] /interface ovpn-server server print 
                     enabled: yes
                        port: 1194
                        mode: ip
                     netmask: 24
                 mac-address: FE:A5:57:72:9D:EC
                     max-mtu: 1500
           keepalive-timeout: 60
             default-profile: default
                 certificate: server
  require-client-certificate: no
                        auth: sha1,md5
                      cipher: blowfish128,aes128

Icon-warn.png

Warning: It is very important that the date on the router is within the range of the installed certificate's date of expiration. To overcome any certificate verification problems, enable NTP date synchronization on both server and client.


Monitoring

Monitor command can be used to monitor the status of the tunnel on both client and server.

[admin@dzeltenais_burkaans] /interface ovpn-server monitor 0
     status: "connected"
     uptime: 17m47s
  idle-time: 17m47s
       user: "test"
  caller-id: "10.1.101.18:43886"
        mtu: 1500

Read-only properties

Property Description
status () Current status. Value other than "connected" indicates that there are some problems establishing tunnel.
uptime (time) Elapsed time since tunnel was established.
idle-time (time) Elapsed time since last activity on the tunnel.
user (string) Username used to establish the tunnel.
mtu (integer) Negotiated and used MTU
caller-id (IP:ID) Source IP and Port of client.

Application Examples

Setup Overview

Ipsec-road-warrior.png

Assume that Office public IP address is 2.2.2.2 and we want two remote OVPN clients to have access to 10.5.8.20 and 192.168.55.0/24 networks behind office gateway.

Creating Certificates

All certificates can be created on RadioOS server using certificate manager. See example >>.

For simplest setup you need only ovpn server certificate.

Server Config

First step is to create ip pool from which client addresses will be assigned and some users

/ip pool add name=ovpn-pool range=192.168.77.2-192.168.77.254

/ppp profile add name=ovpn local-address=192.168.77.1 remote-address=ovpn-pool
/ppp secret
  add name=client1 password=123 profile=ovpn
  add name=client2 password=234 profile=ovpn

Assume that server certificate is already created and named "server"

/interface ovpn-server server set enabled=yes certificate=server

Client Config

RadioOS client

Since RadioOS does not support route-push you need to add manually which networks you want to access over the tunnel.

/interface ovpn-client
  add name=ovpn-client1 connect-to=2.2.2.2 user=client1 password=123 disabled=no
/ip route 
  add dst-address=10.5.8.20 gateway=ovpn-client1
  add dst-address=192.168.55.0/24 gateway=ovpn-client1
/ip firewall nat add chain=srcnat action=masquerade out-interface=ovpn-client1


Linux Client config

dev tun
proto tcp-client

remote 2.2.2.2 1194

tls-client

user nobody
group nogroup

#comp-lzo # Do not use compression.

# More reliable detection when a system loses its connection.
ping 15
ping-restart 45
ping-timer-rem
persist-tun
persist-key

mute-replay-warnings

verb 3

cipher BF-CBC
auth SHA1
pull

auth-user-pass auth.cfg 

The file auth.cfg holds your username/password combination. On the first line must be the username and on the second line your password.

client2
234


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