How-to VPN: Private Internet Access (PIA) and MikroTik Router

First create a vpn profile to use when creating l2tp/pptp connections
to privateinternetaccess.

/ppp profile add change-tcp-mss=yes \
comment="PIA VPN" \
dns-server=209.222.18.222,209.222.18.218 \
name=privateinternetaccess only-one=no \
use-compression=no use-encryption=required \
use-ipv6=no use-mpls=no use-upnp=no

Create the l2tp interface

/interface l2tp-client add \
comment="PIA VPN Netherlands" \
connect-to=nl.privateinternetaccess.com \
disabled=no name=pia-de-l2tp \
profile=privateinternetaccess \
user=[l2tp-username] \
password=[l2tp-password]

• [l2tp-username] Your PIA username for l2tp/pptp/socks connections beginning with ‘x’ (not ‘p’!)
• [l2tp-password] Your PIA password for l2tp/pptp/socks connections

Create a firewall mangle rule to mark IPv4 traffic we want to
go through the VPN.

/ip firewall mangle add \
action=mark-routing \
chain=prerouting \
comment="PIA VPN Netherlands" \
new-routing-mark="PPTP RM" \
passthrough=yes \
src-address=[ip-range-to-forward-through-vpn]

[ip-range-to-forward-through-vpn] Fx. 192.168.1.0/24 or 192.168.1.2-192.168.1.254

Create the NAT rule and tell it to use the VPN interface.

/ip firewall nat add \
action=masquerade chain=srcnat \
comment="PIA VPN Netherlands" \
out-interface=pia-de-l2tp

Create a corresponding default route to match the previous NAT
rule. Which only get used when IPv4 traffic has been marked with
‘PPTP RM’.

/ip route add \
comment="PIA VPN Netherlands" \
disabled=yes distance=1 \
gateway=pia-de-l2tp routing-mark="PPTP RM"

Now you should see traffic from clients in the IPv4 range
of [ip-range-to-forward-through-vpn] go through the VPN.

NB: If you want to use another country apart from Netherlands. Check out Private Internet Access list of locations here: PIA VPN Tunnel Network