@node Example usage
@section Example usage

Let's assume that there is some insecure link between your computer and
WiFi-reachable gateway.

@itemize @bullet
@item You have got @code{wlan0} NIC with 192.168.0/24 network on it.
@item You want to create virtual encrypted and authenticated 172.16.0/24
network and use it as a default transport.
@item @code{wlan0} MTU is 1500, 20 bytes overhead per IPv4. So MTU for
GoVPN is 1500 - 20 - 8 = 1472.
@item During startup client and server will say that TAP interface MTU
is 1432.
@end itemize

@strong{Install}. At first you must @ref{Installation, install} this
software: download, check the signature, compile.

Do not forget about setting @code{GOMAXPROC} environment variable for
using more than one CPU on both sides:

@example
% export GOMAXPROC=4
@end example

@strong{Prepare the server}. Create the new client, named (for example)
"Alice":

@example
% ./utils/newclient.sh Alice
Place verifier to peers/6d4ac605ce8dc37c2f0bf21cb542a713/verifier
@end example

"6d4ac605ce8dc37c2f0bf21cb542a713" -- is the new client's identity.

@strong{Prepare the client}. Generate @ref{Verifier} for known client
identity:

@example
% ./utils/storekey.sh /tmp/passphrase
Enter passphrase:[my secure passphrase is here]
% govpn-verifier -id 6d4ac605ce8dc37c2f0bf21cb542a713 -key /tmp/passphrase
562556cc9ecf0019b4cf45bcdf42706944ae9b3ac7c73ad299d83f2d5a169c55
% rm /tmp/passphrase
@end example

"562556cc9ecf0019b4cf45bcdf42706944ae9b3ac7c73ad299d83f2d5a169c55" --
this is verifier itself.

@strong{Save verifier on server}.

@example
% cat > peers/6d4ac605ce8dc37c2f0bf21cb542a713/verifier <<EOF
562556cc9ecf0019b4cf45bcdf42706944ae9b3ac7c73ad299d83f2d5a169c55
EOF
@end example

@strong{Prepare network on GNU/Linux IPv4 server}:

@example
server% echo "echo tap10" >> peers/6d4ac605ce8dc37c2f0bf21cb542a713/up.sh
server% ip addr add 192.168.0.1/24 dev wlan0
server% tunctl -t tap10
server% ip link set mtu 1432 dev tap10
server% ip addr add 172.16.0.1/24 dev tap10
server% ip link set up dev tap10
@end example

@strong{Run server daemon itself}:

@example
server% govpn-server -bind 192.168.0.1:1194 -mtu 1472
@end example

@strong{Prepare network on GNU/Linux IPv4 client}:

@example
client% umask 066
client% utils/storekey.sh key.txt
client% ip addr add 192.168.0.2/24 dev wlan0
client% tunctl -t tap10
client% ip link set mtu 1432 dev tap10
client% ip addr add 172.16.0.2/24 dev tap10
client% ip link set up dev tap10
client% ip route add default via 172.16.0.1
@end example

@strong{Run client daemon itself}:
@example
client% govpn-client \
    -key key.txt \
    -id 6d4ac605ce8dc37c2f0bf21cb542a713 \
    -iface tap10 \
    -remote 192.168.0.1:1194 \
    -mtu 1472
@end example

@strong{FreeBSD IPv6 similar client-server example}:

@example
server% ifconfig em0 inet6 fe80::1/64
server% govpn-server -bind "fe80::1%em0"
@end example

@example
client% ifconfig me0 inet6 -ifdisabled auto_linklocal
client% ifconfig tap10
client% ifconfig tap10 inet6 fc00::2/96 mtu 1412 up
client% route -6 add default fc00::1
client% govpn-client \
    -key key.txt \
    -id 6d4ac605ce8dc37c2f0bf21cb542a713 \
    -iface tap10 \
    -remote "[fe80::1%me0]":1194
@end example