Forwarding additional ports

r0d3r1ck

Apologies for the noob post.

With some effort I have managed to get OpenVPN to work for remote RDP connections to my home pc from both a laptop and an android client. What i would like to do now is allow my emails to sync on my android emails (i believe it is port 995 incoming and 465 outgoing) whilst connected to my OpenVPN server. Any help would be appreciated. If I start tinkering I will inevitably break the progress that i have made.

Also, please let me know if you spot anyway i can harden (or improve security) to my setup.

Server Config

push "route 10.9.8.0 255.255.255.0"
;push "route 192.168.0.0 255.255.255.0"

push "dhcp-option DNS 192.168.66.1"
server 192.168.66.0 255.255.255.0

dev tun0
proto tcp
port 443
keepalive 10 120
dh /tmp/openvpn/dh.pem
ca /tmp/openvpn/ca.crt
cert /tmp/openvpn/cert.pem
key /tmp/openvpn/key.pem
comp-lzo yes
script-security 2
verb 5
management localhost 5001

Firewall Config

# Accept OPENVPN Port 443
iptables -I INPUT 1 -p tcp --dport 443 -j ACCEPT 

# Accept DHCP requests Port 68
iptables -I INPUT 2 -p udp --dport 68 -j ACCEPT

# Allow traffic to be forwarded to 192.168.66.0/24 OpenVPN server subnet:
iptables -I FORWARD 1 --source 192.168.66.0/24 -j ACCEPT 

# Allow traffic to the OPENVPN tunnel
iptables -I FORWARD -i br0 -o tun0 -j ACCEPT 
iptables -I FORWARD -i tun0 -o br0 -j ACCEPT

# NAT the traffic to the subnet
iptables -t nat -A POSTROUTING -s 192.168.66.0/24 -o eth0 -j MASQUERADE

Client Config

##############################################
# Sample client-side OpenVPN 2.0 config file #
# for connecting to multi-client server.     #
#                                            #
# This configuration can be used by multiple #
# clients, however each client should have   #
# its own cert and key files.                #
#                                            #
# On Windows, you might want to rename this  #
# file so it has a .ovpn extension           #
##############################################


# Specify that we are a client and that we
# will be pulling certain config file directives
# from the server.
client

# Use the same setting as you are using on
# the server.
# On most systems, the VPN will not function
# unless you partially or fully disable
# the firewall for the TUN/TAP interface.
;dev tap
dev tun

# Windows needs the TAP-Win32 adapter name
# from the Network Connections panel
# if you have more than one.  On XP SP2,
# you may need to disable the firewall
# for the TAP adapter.
;dev-node MyTap

# Are we connecting to a TCP or
# UDP server?  Use the same setting as
# on the server.
proto tcp
#proto udp

# The hostname/IP and port of the server.
# You can have multiple remote entries
# to load balance between the servers.
remote 77.96.41.150 443

# Choose a random host from the remote
# list for load-balancing.  Otherwise
# try hosts in the order specified.
;remote-random

# Keep trying indefinitely to resolve the
# host name of the OpenVPN server.  Very useful
# on machines which are not permanently connected
# to the internet such as laptops.
resolv-retry infinite

# Most clients don't need to bind to
# a specific local port number.
nobind

# Downgrade privileges after initialization (non-Windows only)
;user nobody
;group nobody

# Try to preserve some state across restarts.
persist-key
persist-tun

# If you are connecting through an
# HTTP proxy to reach the actual OpenVPN
# server, put the proxy server/IP and
# port number here.  See the man page
# if your proxy server requires
# authentication.
;http-proxy-retry # retry on connection failures
;http-proxy [proxy server] [proxy port #]

# Wireless networks often produce a lot
# of duplicate packets.  Set this flag
# to silence duplicate packet warnings.
;mute-replay-warnings

# SSL/TLS parms.
# See the server config file for more
# description.  It's best to use
# a separate .crt/.key file pair
# for each client.  A single ca
# file can be used for all clients.
ca ca.crt
cert client1.crt
key client1.key

# Verify server certificate by checking
# that the certicate has the nsCertType
# field set to "server".  This is an
# important precaution to protect against
# a potential attack discussed here:
#  http://openvpn.net/howto.html#mitm
#
# To use this feature, you will need to generate
# your server certificates with the nsCertType
# field set to "server".  The build-key-server
# script in the easy-rsa folder will do this.
;ns-cert-type server

# If a tls-auth key is used on the server
# then every client must also have the key.
;tls-auth ta.key 1

# Select a cryptographic cipher.
# If the cipher option is used on the server
# then you must also specify it here.
;cipher x

# Enable compression on the VPN link.
# Don't enable this unless it is also
# enabled in the server config file.
comp-lzo
route-ipv6 ::/0
route 0.0.0.0 0.0.0.0 vpn_gateway


# Set log file verbosity.
verb 5

# Silence repeating messages
;mute 20

# needed by openvpn
float

# next 3 entries added to resolve domains
redirect-gateway def1 bypass-dhcp

# Any?DNS?can go here, i use OpenDNS
dhcp-option DNS 208.67.222.222
dhcp-option DNS 208.67.220.220
remote-cert-tls server
persist-tun

Traffic

r0d3r1ck wroteWhat i would like to do now is allow my emails to sync on my android emails (i believe it is port 995 incoming and 465 outgoing) whilst connected to my OpenVPN server

You probably want to redirect your client gateway:
HOWTO: Routing all client traffic (including web-traffic) through the VPN

Unless you only want to do this for mail ports .. in which case you need policy based routing .. I don't know if you can do that with android.

r0d3r1ck wroteplease let me know if you spot anyway i can harden (or improve security)

See --tls-auth in The Manual v23x

r0d3r1ck wrote# Allow traffic to the OPENVPN tunnel
iptables -I FORWARD -i br0 -o tun0 -j ACCEPT
iptables -I FORWARD -i tun0 -o br0 -j ACCEPT

hmm .. do you need a bridge .. is the server a router ?

r0d3r1ck

Thanks Traffic for your swift response. I have not had chance to try this out yet, as I tend to use my VPN all the time. I will try and disable the bridging lines -- I think I was trying to restrict wifi traffic to the VPN so that I could control it. I have another way of doing this now.

r0d3r1ck

Hi Traffic

Thank you for your quick and kind help. I managed to add the TLS Auth flag. I also commented out the bridge with no issues.

I am still struggling with tunnelling the client traffic. I have made made changes to comply with the linked instructions, and even tried a number of different configs, but still no joy.

The curious thing is that port 3389 (used to RDP) seems to tunnel over the VPN to the destination pc's IP address without any problem. I can also ping my NAS and view my files in windows explorer (which is connected to the router and probably is uPnP). Yet I cannot ping my router itself, nor the internal local computer that I can log into using RDP.

My default gateway from my external remote client (the laptop in the field) seems to be wrong. It says 192.168.66.5, which is the exit point of the tunnel

ifconfig 192.168.66.6 192.168.66.5

. According to the server.config

server 192.168.66.0 255.255.255.0

I would have thought this should be 192.168.66.1.

r0d3r1ck

Thanks for all that. I managed to add the tls-auth and remove the bridging ok.

i am still looking at my router firewall log which is blocking inbound traffic from 192.168.66.6 (my openvpn client) to 192.168.66.1 (port 53 dnslookup). I have tried adding

iptables -A INPUT -s 192.168.66.6 -j ACCEPT

but this didn't work. it appears that the router doesn't know that it is the vpn server at 192.168.66.1.

Traffic

Please post your new configs.

FYI: if your server LAN is 192.168.66.0/24 then this is conflicting:

r0d3r1ck wroteServer Config
Code:

server 192.168.66.0 255.255.255.0

You should use the default IP address 10.8/24