Openvpn with fixed ips

Introduction

We already explored openvpn with dhcp...here we will have fixed ips without dhcp...here's the setting:

• isc-dhcp40-server
• bind95
• openvpn

with this setup we will be able to see the internal network from an external connection:

Setup

here's openvpn.conf:

ca /usr/local/etc/openvpn/keys/ca.crt
cert /usr/local/etc/openvpn/keys/server.crt
key /usr/local/etc/openvpn/keys/server.key
dh /usr/local/etc/openvpn/keys/dh1024.pem
# USE TAP ON SERVER AND CLIENT SIDE !
dev tap
#ifconfig-pool-persist ipp.txt
# replace 192.168.1.101 with the VPN IP
server-bridge 192.168.0.1 255.255.254.0 192.168.0.2 192.168.0.250
keepalive 10 120
client-to-client
verb 3
duplicate-cn
push "route-gateway 192.168.0.1"
push "dhcp-option DNS 192.168.0.1" # push DNS entries to openvpn client
push "redirect-gateway"
#redirect-gateway
client-config-dir /usr/local/etc/openvpn/config

here's the content of a client config in /usr/local/etc/openvpn/config i named this file with the name of the certificate: port4 : that is needed so it will assign this ip to the owner of the port4 certificate

ifconfig-push 192.168.0.107 255.255.254.0

here's the content of /usr/local/etc/dhcpd.conf

option domain-name "workgroup";
ddns-update-style none;
class "openvpn" {
        match if substring (hardware,1,2) = 00:ff;
} 

subnet 192.168.1.0 netmask 255.255.255.0 {
        option routers 192.168.1.1;
        option domain-name-servers 192.168.1.1;
        pool {
                deny members of "openvpn";
                allow unknown-clients;
                allow known-clients;
                ddns-updates off;
                range 192.168.1.100 192.168.1.199;
        }
} 

host port4 {
  hardware ethernet 00:16:6f:b9:02:a4;
  fixed-address 192.168.1.107;
}

here we match for mac address that starts by 00:ff,because tap devices do,and we assign them to the openvpn class... then we allow known and unknown clients but deny the right of the client's tap interface to get an ip in this range then at the end we assign an ip to a client...that makes the ports redirections easier