[OpenVPN home] [Date Prev] [Date Index] [Date Next]
[OpenVPN mailing lists] [Thread Prev] [Thread Index] [Thread Next]
Google
 
Web openvpn.net

[Openvpn-users] Intermittent multicast routing problem


  • Subject: [Openvpn-users] Intermittent multicast routing problem
  • From: Sean Lisse <lisse@xxxxxxxxxxxx>
  • Date: Tue, 18 Dec 2007 11:25:07 -0500

OpenVPN support and volunteers;

I've been wrestling for about a week now with setting up an openvpn network to support a multi-site experiment. The software used in the experiment talks among machines using multicast, and I'm having problems getting them to talk to each other. I would appreciate any help that you can offer.

Interestingly, the same network setup (minus the tweak of changing the port # on which openvpn listens) has worked with this same software in the past. Current symptoms of the problem - I can connect the two windows XP end-point testing machines to the network without a problem. Each of them can ping the other's OpenVPN-assigned IP address, so I know that there's unicast connectivity. I've checked the routing tables and manually upped the priority of routing multicast over the openvpn virtual interface on each of them (for some reason the openvpn-added multicast route starts with a higher metric #, which is lower priority).

When I run a packet capture utility (tcpdump) on the openvpn server, I can see traffic flowing by on the openvpn port when I ping. However, I see no traffic when I attempt a multicast connection. This led me to suspect a multicast routing issue (perhaps multicast was going out on the real interface rather than the virtual one), but as I stated above, I tried manual manipulation of the routing table with no luck.

I've tried just about everything that I can think of including adding 'redirect-gateway def1' to each client's configuration, just in case that makes the routing bettter... no dice.

I've attached a copy of my client .ovpn file, in case that helps with the debugging.

 Thanks,
      Sean Lisse
      AI Engineer (and OpenVPN maintainer)
      Soar Technology

##############################################
# 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           #
##############################################

#Testing
redirect-gateway def1

# 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 collaboration.soartech.com 1194
remote collaboration.soartech.com 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 nogroup

# 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 backup.aa.soartech.com.crt
key backup.aa.soartech.com.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

# Set log file verbosity.
verb 3

# Silence repeating messages
mute 20
_______________________________________________
Openvpn-users mailing list
Openvpn-users@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/openvpn-users