Technical data

4. Packages
an additional DNS server) it will be assumed that a DNS server is listening on the IP of the
other end of the tunnel (see OPENVPN_x_REMOTE_VPN_IP (Page 166)). On the remote router
incoming DNS queries have to allowed in this case. (i.e. via OPENVPN_x_INPUT_y=’tmpl:dns
ACCEPT’)
OPENVPN_x_ROUTE_x_DOMAIN Default: OPENVPN_x_ROUTE_x_DOMAIN=”
Different subnets can have different domains assigned. Per OPENVPN_x_ROUTE_y one ac-
cording domain can be configured. If a OPENVPN_x_ROUTE_y_DNSIP exists for the domain,
it will be used, else the one set at OPENVPN_x_DNSIP. The effect is the same as with
OPENVPN_x_DOMAIN but this method allows better documentation.
OPENVPN_x_DNSIP Default: OPENVPN_x_DNSIP=”
If the tunnel end point is not the appropriate DNS server set the IP of the appropriate
one here. If this is empty the one at OPENVPN_x_REMOTE_VPN_IP (Page 166) will be used.
OPENVPN_x_ROUTE_x_DNSIP Default: OPENVPN_x_ROUTE_x_DNSIP=”
Multiple subnets routed can also have different DNS servers - define one per
OPENVPN_x_ROUTE_x (Page 168) here.
4.14.5. Expert Settings
Settings described in this chapter are all optional and should only be changed if the OpenVPN
connection is working but should be optimized (for example by the use of another encryption
algorithm).
All settings in OPENVPN_DEFAULT_ are otional. This means they don’t have to be written in
the config file. If an entry is missing in openvpn.txt the OpenVPN start script will use the
default value described here. If you don’t want to change this defaults do not write them to
the openvpn.txt config file!
General Settings
OPENVPN_DEFAULT_CIPHER Default: OPENVPN_DEFAULT_CIPHER=’BF-CBC’
One of the available encryption methods. Method ’BF-CBC’ is used as a default by all
OpenVPN versions (also non-fli4l specific versions).
OPENVPN_DEFAULT_COMPRESS Default: OPENVPN_DEFAULT_COMPRESS=’yes’
OpenVPN uses adaptive LZO data compression to enlarge the bandwidth of a connection.
Adaptive means OpenVPN recognizes by itself when i.e. already compressed zip files are
sent over an OpenVPN connection. In such case data compression will be switched off
until data is sent that will benefit from data compression. There is nearly no cause for
deactivating data compression because this enlarges bandwidth at nearly no cost. Only
disadvantage of data compression is a small increase of latency by some milliseconds.
For online games via VPN which need a ”good” ping, i.e. low latency it may be wise to
deactivate data compression.
OPENVPN_DEFAULT_CREATE_SECRET Default: OPENVPN_DEFAULT_CREATE_SECRET=’no’
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