linux vpn

Red Squirrel · 12-23-2008, 11:11 PM

Quote:

Originally Posted by billymayday

Try

push "route 10.1.1.0 255.255.255.0"

in server.conf

Did that, but do I also need to add a static route at the server level so that the vpn subnet is valid throughout my network? I think that may be the issue. I have a dlink DIR-615 router and there's no static route option so I'm pretty much dead in the water until I buy a new router. I just bought that too.

billymayday · 12-23-2008, 11:26 PM

Is that router the gateway?

See http://openvpn.net/index.php/documen...wto.html#scope

I wouldn't worry too much. You've now established that the basic concept works, and that your problem previously was (pretty much for sure) that your bridge wasn't set up correctly. If need be, you can go back to getting that working.

Red Squirrel · 12-26-2008, 10:19 PM

ok reverted back to dev tap. What are things I should be looking for with the bridge?

Should the bridge IP be the IP of the vpn box, or should it be another IP? That's the part I'm confused with, I don't know what any of the IPs for the settings are supose to represent.

billymayday · 12-26-2008, 10:39 PM

I found this rather interesting discussion. Looks like a you can't set up a proper bridge with only one NIC

http://linux.derkeiler.com/Newsgroup.../msg00252.html

Red Squirrel · 12-26-2008, 11:18 PM

Hmm well this kinda sucks then. So guess dev tun is only way. I'll see if I can get that working then. Was getting a little further with it, just need to get the routing to work.

billymayday · 12-26-2008, 11:21 PM

How much does a NIC cost? 20 bucks or so?

Red Squirrel · 12-26-2008, 11:35 PM

Thats not really the issue. The server wont handle another. the only pci slot left wont boot if I put something in it, and I tried a usb one and it wont work either. So I'm dead in the water.

Trying to get dev tun to work, on my internal network I do have the ability to add static routes, and for my external I can always setup a smoothwall vm then put the vm server behind it.

billymayday · 12-26-2008, 11:39 PM

Makes sense.

What isn't working on the routed setup?

Red Squirrel · 12-26-2008, 11:42 PM

for routed I can ping the vpn server itself but not beyond. I set a static route but does not seem to do anything.

This is my server config:

Code:

#################################################
# Sample OpenVPN 2.0 config file for            #
# multi-client server.                          #
#                                               #
# This file is for the server side              #
# of a many-clients <-> one-server              #
# OpenVPN configuration.                        #
#                                               #
# OpenVPN also supports                         #
# single-machine <-> single-machine             #
# configurations (See the Examples page         #
# on the web site for more info).               #
#                                               #
# This config should work on Windows            #
# or Linux/BSD systems.  Remember on            #
# Windows to quote pathnames and use            #
# double backslashes, e.g.:                     #
# "C:\\Program Files\\OpenVPN\\config\\foo.key" #
#                                               #
# Comments are preceded with '#' or ';'         #
#################################################

# Which local IP address should OpenVPN
# listen on? (optional)
#local 10.1.1.15

# Which TCP/UDP port should OpenVPN listen on?
# If you want to run multiple OpenVPN instances
# on the same machine, use a different port
# number for each one.  You will need to
# open up this port on your firewall.
# #default is 1194
port 1194

# TCP or UDP server?
;proto tcp
proto udp

# "dev tun" will create a routed IP tunnel,
# "dev tap" will create an ethernet tunnel.
# Use "dev tap0" if you are ethernet bridging
# and have precreated a tap0 virtual interface
# and bridged it with your ethernet interface.
# If you want to control access policies
# over the VPN, you must create firewall
# rules for the the TUN/TAP interface.
# On non-Windows systems, you can give
# an explicit unit number, such as tun0.
# On Windows, use "dev-node" for this.
# On most systems, the VPN will not function
# unless you partially or fully disable
# the firewall for the TUN/TAP interface.
;dev tap0
dev tun

# Windows needs the TAP-Win32 adapter name
# from the Network Connections panel if you
# have more than one.  On XP SP2 or higher,
# you may need to selectively disable the
# Windows firewall for the TAP adapter.
# Non-Windows systems usually don't need this.
;dev-node tap0

# SSL/TLS root certificate (ca), certificate
# (cert), and private key (key).  Each client
# and the server must have their own cert and
# key file.  The server and all clients will
# use the same ca file.
#
# See the "easy-rsa" directory for a series
# of scripts for generating RSA certificates
# and private keys.  Remember to use
# a unique Common Name for the server
# and each of the client certificates.
#
# Any X509 key management system can be used.
# OpenVPN can also use a PKCS #12 formatted key file
# (see "pkcs12" directive in man page).
ca /etc/openvpn/easy-rsa/keys/ca.crt
cert /etc/openvpn/easy-rsa/keys/server.crt
key /etc/openvpn/easy-rsa/keys/server.key  # This file should be kept secret

# Diffie hellman parameters.
# Generate your own with:
#   openssl dhparam -out dh1024.pem 1024
# Substitute 2048 for 1024 if you are using
# 2048 bit keys.
dh /etc/openvpn/easy-rsa/keys/dh1024.pem

# Configure server mode and supply a VPN subnet
# for OpenVPN to draw client addresses from.
# The server will take 10.8.0.1 for itself,
# the rest will be made available to clients.
# Each client will be able to reach the server
# on 10.8.0.1. Comment this line out if you are
# ethernet bridging. See the man page for more info.
server 10.1.10.0 255.255.255.0

# Maintain a record of client <-> virtual IP address
# associations in this file.  If OpenVPN goes down or
# is restarted, reconnecting clients can be assigned
# the same virtual IP address from the pool that was
# previously assigned.
ifconfig-pool-persist ipp.txt

# Configure server mode for ethernet bridging.
# You must first use your OS's bridging capability
# to bridge the TAP interface with the ethernet
# NIC interface.  Then you must manually set the
# IP/netmask on the bridge interface, here we
# assume 10.8.0.4/255.255.255.0.  Finally we
# must set aside an IP range in this subnet
# (start=10.8.0.50 end=10.8.0.100) to allocate
# to connecting clients.  Leave this line commented
# out unless you are ethernet bridging.
;server-bridge 10.1.1.15 255.255.255.0 10.1.1.201 10.1.1.254

# Push routes to the client to allow it
# to reach other private subnets behind
# the server.  Remember that these
# private subnets will also need
# to know to route the OpenVPN client
# address pool (10.8.0.0/255.255.255.0)
# back to the OpenVPN server.
;push "route 192.168.10.0 255.255.255.0"
push "route 10.1.1.0 255.255.255.0"


# To assign specific IP addresses to specific
# clients or if a connecting client has a private
# subnet behind it that should also have VPN access,
# use the subdirectory "ccd" for client-specific
# configuration files (see man page for more info).

# EXAMPLE: Suppose the client
# having the certificate common name "Thelonious"
# also has a small subnet behind his connecting
# machine, such as 192.168.40.128/255.255.255.248.
# First, uncomment out these lines:
;client-config-dir ccd
;route 192.168.40.128 255.255.255.248
# Then create a file ccd/Thelonious with this line:
#   iroute 192.168.40.128 255.255.255.248
# This will allow Thelonious' private subnet to
# access the VPN.  This example will only work
# if you are routing, not bridging, i.e. you are
# using "dev tun" and "server" directives.

# EXAMPLE: Suppose you want to give
# Thelonious a fixed VPN IP address of 10.9.0.1.
# First uncomment out these lines:
;client-config-dir ccd
;route 10.9.0.0 255.255.255.252
# Then add this line to ccd/Thelonious:
#   ifconfig-push 10.9.0.1 10.9.0.2

# Suppose that you want to enable different
# firewall access policies for different groups
# of clients.  There are two methods:
# (1) Run multiple OpenVPN daemons, one for each
#     group, and firewall the TUN/TAP interface
#     for each group/daemon appropriately.
# (2) (Advanced) Create a script to dynamically
#     modify the firewall in response to access
#     from different clients.  See man
#     page for more info on learn-address script.
;learn-address ./script

# If enabled, this directive will configure
# all clients to redirect their default
# network gateway through the VPN, causing
# all IP traffic such as web browsing and
# and DNS lookups to go through the VPN
# (The OpenVPN server machine may need to NAT
# the TUN/TAP interface to the internet in
# order for this to work properly).
# CAVEAT: May break client's network config if
# client's local DHCP server packets get routed
# through the tunnel.  Solution: make sure
# client's local DHCP server is reachable via
# a more specific route than the default route
# of 0.0.0.0/0.0.0.0.
;push "redirect-gateway def1"

# Certain Windows-specific network settings
# can be pushed to clients, such as DNS
# or WINS server addresses.  CAVEAT:
# http://openvpn.net/faq.html#dhcpcaveats
push "dhcp-option DNS 10.1.1.10"
;push "dhcp-option WINS 10.8.0.1"


# Uncomment this directive to allow different
# clients to be able to "see" each other.
# By default, clients will only see the server.
# To force clients to only see the server, you
# will also need to appropriately firewall the
# server's TUN/TAP interface.
;client-to-client

# Uncomment this directive if multiple clients
# might connect with the same certificate/key
# files or common names.  This is recommended
# only for testing purposes.  For production use,
# each client should have its own certificate/key
# pair.
#
# IF YOU HAVE NOT GENERATED INDIVIDUAL
# CERTIFICATE/KEY PAIRS FOR EACH CLIENT,
# EACH HAVING ITS OWN UNIQUE "COMMON NAME",
# UNCOMMENT THIS LINE OUT.
;duplicate-cn

# The keepalive directive causes ping-like
# messages to be sent back and forth over
# the link so that each side knows when
# the other side has gone down.
# Ping every 10 seconds, assume that remote
# peer is down if no ping received during
# a 120 second time period.
keepalive 10 120

# For extra security beyond that provided
# by SSL/TLS, create an "HMAC firewall"
# to help block DoS attacks and UDP port flooding.
#
# Generate with:
#   openvpn --genkey --secret ta.key
#
# The server and each client must have
# a copy of this key.
# The second parameter should be '0'
# on the server and '1' on the clients.
;tls-auth ta.key 0 # This file is secret

# Select a cryptographic cipher.
# This config item must be copied to
# the client config file as well.
;cipher BF-CBC        # Blowfish (default)
cipher AES-128-CBC   # AES
;cipher DES-EDE3-CBC  # Triple-DES

;tls-server

# Enable compression on the VPN link.
# If you enable it here, you must also
# enable it in the client config file.
comp-lzo

# The maximum number of concurrently connected
# clients we want to allow.
;max-clients 100

# It's a good idea to reduce the OpenVPN
# daemon's privileges after initialization.
#
# You can uncomment this out on
# non-Windows systems.
;user nobody
;group nobody

# The persist options will try to avoid
# accessing certain resources on restart
# that may no longer be accessible because
# of the privilege downgrade.
persist-key
persist-tun

# Output a short status file showing
# current connections, truncated
# and rewritten every minute.
status openvpn-status.log

# By default, log messages will go to the syslog (or
# on Windows, if running as a service, they will go to
# the "\Program Files\OpenVPN\log" directory).
# Use log or log-append to override this default.
# "log" will truncate the log file on OpenVPN startup,
# while "log-append" will append to it.  Use one
# or the other (but not both).
;log         openvpn.log
;log-append  openvpn.log

# Set the appropriate level of log
# file verbosity.
#
# 0 is silent, except for fatal errors
# 4 is reasonable for general usage
# 5 and 6 can help to debug connection problems
# 9 is extremely verbose
verb 4

# Silence repeating messages.  At most 20
# sequential messages of the same message
# category will be output to the log.
;mute 20

And this is the client setup:

Code:

client
dev tun
proto udp
# change this to your server's address
remote home.iceteks.net 1194
resolv-retry infinite
nobind

persist-key
persist-tun

# Point the key and crt files to
# the ones for this user

ca C:\\openvpnkeys\\ca.crt
cert C:\\openvpnkeys\\ryan.crt
key C:\\openvpnkeys\\ryan.key
#ensure that we are talking to a server

;tls-client

ns-cert-type server

#confirm we are talking to the correct server
#tls-auth C:\\openvpnkeys\\ta.key 1
# Select a cryptographic cipher.
# If the cipher option is used on the server
# then you must also specify it here.

cipher AES-128-CBC
;cipher BF-CBC

# Enable compression on the VPN link.
comp-lzo


#fragment large packets
# I found I needed this for some games but it is
# not required
#fragment 1400
# enable user/pass authentication
#auth-user-pass
verb 3

On my router I have a static route to direct all 10.1.10.0/24 to 10.1.1.15 is that how I have to do it?

Also from the vpn tunnel if I tracert to 10.1.1.15 it goes fine if I do any other ip in that range it does not even hit the first gateway. I think the packet is getting there but the server on the lan does not know how to send back the response to the vpn client, if I do tcpdump -i tun0 I can see the echo request coming through from the vpn client.

billymayday · 12-26-2008, 11:50 PM

Here's my server route output

Code:

# route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
10.8.0.2        *               255.255.255.255 UH    0      0        0 tun0
10.8.0.0        10.8.0.2        255.255.255.0   UG    0      0        0 tun0
192.168.1.0     *               255.255.255.0   U     0      0        0 eth1
192.168.0.0     *               255.255.255.0   U     0      0        0 eth0
169.254.0.0     *               255.255.0.0     U     0      0        0 eth1
default         192.168.0.1     0.0.0.0         UG    0      0        0 eth0

Where 192.168.0. is WAN ans 192.168.1. is LAN

Red Squirrel · 12-26-2008, 11:53 PM

Hmm mine looks similar, I can also ping 10.1.10.6 (the vpn client) so I know the vpn server can talk to the client. I can't ping that from any other server though.

Code:

[root@vpnsrv openvpn]# route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
10.1.10.2       *               255.255.255.255 UH    0      0        0 tun0
10.1.10.0       10.1.10.2       255.255.255.0   UG    0      0        0 tun0
10.1.1.0        *               255.255.255.0   U     0      0        0 eth0
link-local      *               255.255.0.0     U     0      0        0 eth0
default         router.loc      0.0.0.0         UG    0      0        0 eth0

This is my router's routing table (router.loc = 10.1.1.1)

Code:

Destination IP	Netmask	Gateway	       Metric	Interface
10.10.0.255	255.255.255.255	0.0.0.0	1	WAN
10.10.0.2	255.255.255.255	0.0.0.0	1	WAN
10.10.0.0	255.255.255.0	0.0.0.0	1	WAN
0.0.0.0	        0.0.0.0	         10.10.0.1	1	WAN
10.1.1.255	255.255.255.255	0.0.0.0	1	LAN
10.1.1.1	255.255.255.255	0.0.0.0	1	LAN
10.1.10.0	255.255.255.0	10.1.1.15	1	LAN
10.1.1.0	255.255.255.0	0.0.0.0	1	LAN

billymayday · 12-27-2008, 12:12 AM

What's your server vpn IP, is it 10.1.10.1?

Assuming so, can you ping that IP from any other machines on you LAN?

Red Squirrel · 12-27-2008, 12:15 AM

Yeah that's the IP on tun0 and I can ping it from lan clients. I can't ping .2 though (should I be able to?)

The "real" IP of the vpn server is 10.1.1.15 though. (eth0)

Red Squirrel · 12-27-2008, 12:22 AM

WOOT! got it working

I forgot this part:

echo 1 > /proc/sys/net/ipv4/ip_forward

on the server. What exactly does that command do though and does it have to be done at every system startup?

Well thanks a lot for the help, I'm glad I finally got this working. Now I should save everything I have, scrap it then try to recreate it so I can document it for future use.

billymayday · 12-27-2008, 12:33 AM

It's always something simple.

Stick that line in the end of /etc/rc.local, and it will happen on boot.

Edit - sorry, it just tells the system that you are happy for packets to get forwarded from one interface to another. It's a security thing - don't allow it unless you want it.