Smuxi

With a firewall disabled on the server side
connected to the net with a public address
connected to a vpn: 10.8.0.*

The client fails to connect to the server.

Here is the ngrep dump
$ sudo ngrep -d eth1 port 7689

######
T 88.170.xx.xx:35848 -> 193.51.xx.xx:7689 [AP]
.NET......%.......*...tcp://myhost.domainname.fr:7689/SessionManager........app
lication/octet-stream..........................Register.`Smuxi.Engine.Sessi
onManager, smuxi-engine, Version=0.8.0.0, Culture=neutral, PublicKeyToken=n
ull...............sylvestre..... 35fa6ec2540eed3df44c25db2ca0d46c..........
.System.Runtime.Remoting.ObjRef.....uri.typeInfo.envoyInfo.channelInfo.objr
efFlags.....)System.Runtime.Remoting.IRemotingTypeInfo"System.Runtime.Remot
ing.IEnvoyInfo$System.Runtime.Remoting.IChannelInfo......211017ef9_8407_474
1_9164_b476afe3e229/79b8a49_4.rem.................... System.Runtime.Remoti
ng.TypeInfo.....serverType.serverHierarchy.interfacesImplemented........iSm
uxi.Frontend.Gnome.GnomeUI, smuxi-frontend-gnome, Version=0.8.0.0, Culture=
neutral, PublicKeyToken=null...............#System.Runtime.Remoting.Channel
Info.....channelData....................gSmuxi.Engine.PermanentRemoteObject
, smuxi-engine, Version=0.8.0.0, Culture=neutral, PublicKeyToken=null......
........]Smuxi.Engine.IFrontendUI, smuxi-engine, Version=0.8.0.0, Culture=n
eutral, PublicKeyToken=null........................3System.Runtime.Remoting
.Channels.CrossAppDomainData....._ContextID._DomainID._processGuid.........
..........$54eb9d02-5dc4-447f-a70f-2e6f32568219.....1System.Runtime.Remotin
g.Channels.ChannelDataStore....._channelURIs._extraData..$System.Collection
s.DictionaryEntry[].....................tcp://192.168.0.10:36444.
T 193.51.xxx.xxx:7689 -> 88.170.xxx.xxx:35848 [A]
.NET...............................".....................)System.Runtime.Re
moting.RemotingException.....ClassName.Message.InnerException.HelpURL.Stack
TraceString.RemoteStackTraceString.RemoteStackIndex.HResult.Source.Exceptio
nMethod.Data..............System.Collections.IDictionary.....)System.Runtim
e.Remoting.RemotingException......Connection timed out......... at System.
Runtime.Remoting.Channels.Tcp.HostConnectionPool.CreateConnection () [0x000
00] in <filename unknown>:0 . at System.Runtime.Remoting.Channels.Tcp.Host
ConnectionPool.GetConnection () [0x00000] in <filename unknown>:0 . at Sys
tem.Runtime.Remoting.Channels.Tcp.TcpConnectionPool.GetConnection (System.S
tring host, Int32 port) [0x00000] in <filename unknown>:0 . at System.Runt
ime.Remoting.Channels.Tcp.TcpClientTransportSink.ProcessMessage (IMessage m
sg, ITransportHeaders requestHeaders, System.IO.Stream requestStream, ITran
sportHeaders& responseHeaders, System.IO.Stream& responseStream) [0x00000]
in <filename unknown>:0 . at System.Runtime.Remoting.Channels.BinaryClient
FormatterSink.SyncProcessMessage (IMessage msg) [0x00000] in <filename unkn
own>:0 .........Server stack trace: . at System.Runtime.Remoting.Channels.
Tcp.HostConnectionPool.CreateConnection () [0x00000] in <filename unknown>:
0 . at System.Runtime.Remoting.Channels.Tcp.HostConnectionPool.GetConnecti
on () [0x00000] in <filename unknown>:0 . at System.Runtime.Remoting.Chann
els.Tcp.TcpConnectionPo #
T 193.51.xxx.xxx:7689 -> 88.170.xxx.xxx:35848 [AP]
ol.GetConnection (System.String host, Int32 port) [0x00000] in <filename un
known>:0 . at System.Runtime.Remoting.Channels.Tcp.TcpClientTransportSink.
ProcessMessage (IMessage msg, ITransportHeaders requestHeaders, System.IO.S
tream requestStream, ITransportHeaders& responseHeaders, System.IO.Stream&
responseStream) [0x00000] in <filename unknown>:0 . at System.Runtime.Remo
ting.Channels.BinaryClientFormatterSink.SyncProcessMessage (IMessage msg) [
0x00000] in <filename unknown>:0 ..Exception rethrown at [0]: .............
..System.Runtime.Remoting...
##^Z

On the client side, the exception is the following:
2011-08-03 10:12:49,223 [Main] INFO Smuxi.Frontend.EngineManager - Connecting to: tcp://myhost.domainname.fr:7689/SessionManager
2011-08-03 10:15:58,650 [Main] ERROR Smuxi.Frontend.Gnome.EngineManagerDialog - System.Runtime.Remoting.RemotingException: Connection timed out at System.Runtime.Remoting.Channels.Tcp.HostConnectionPool.CreateConnection () [0x00000] in <filename unknown>:0
at System.Runtime.Remoting.Channels.Tcp.HostConnectionPool.GetConnection () [0x00000] in <filename unknown>:0
at System.Runtime.Remoting.Channels.Tcp.TcpConnectionPool.GetConnection (System.String host, Int32 port) [0x00000] in <filename unknown>:0
at System.Runtime.Remoting.Channels.Tcp.TcpClientTransportSink.ProcessMessage (IMessage msg, ITransportHeaders requestHeaders, System.IO.Stream requestStream, ITransportHeaders& responseHeaders, System.IO.Stream& responseStream) [0x00000] in <filename unknown>:0
at System.Runtime.Remoting.Channels.BinaryClientFormatterSink.SyncProcessMessage (IMessage msg) [0x00000] in <filename unknown>:0

Exception rethrown at [1]:

at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke (System.Runtime.Remoting.Proxies.RealProxy rp, IMessage msg, System.Exception& exc, System.Object[]& out_args) [0x00000] in <filename unknown>:0

Please note that the issue does not happen with I am connected on the same network.