Cannot connect to freenx server running on host and guest simultaneously. Port report reported as already open by the connecting client.

[Brandon]

Software Configuration Description

---

We have a Ubuntu 64bit 9.10 server:
Linux sc-vm01-lnx.Stonegate 2.6.31-16-generic #53-Ubuntu SMP Tue Dec 8 04:02:15 UTC 2009 x86_64 GNU/Linux

• This server is using freenx to allow remote graphical sessions.
• The server has a static ip address and is utilizing one NIC:

eth0 Link encap:Ethernet HWaddr 00:1d:09:29:32:5f inet addr:172.27.0.204 Bcast:172.27.3.255 Mask:255.255.252.0

07:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5708 Gigabit Ethernet (rev 12)

Our Guest VM is Ubuntu 64bit 9.10 desktop:
Linux sgintel.stonegate 2.6.31-17-generic #54-Ubuntu SMP Thu Dec 10 17:01:44 UTC 2009 x86_64 GNU/Linux

• The guest uses Network Adapter 1:as the VirtualBox Intel PRO/1000 MT Desktop (Bridged adapter, eth0)
• The guest has a static IP:

eth0 Link encap:Ethernet HWaddr 08:00:27:f2:5d:ca inet addr:172.27.0.206 Bcast:172.27.3.255 Mask:255.255.252.0

• The guest is running freenx server to provide graphical remote sessions.
• VirtualBox Guest Additions are installed at the appropriate version.

---

Problem Description

---

I can successfully connect to either the Host or the Guest using the NX Client but not both at the same time.

When I try to connect to both at the same time, I get an error telling me that TCP Port 11000 is already in use.

I have no trouble using NX Client from my computer to connect to two freenx servers simultaneously if they are on separate physical computers. Therefore, there must be an issue with the way VirtualBox 3.1.2 r56127 is handling network routing dealing with the ports.
The host with 172.27.0.204 has port 11000 open when a client is connected via NX Client.
The guest with 172.27.0.206 has port 11000 open when a client is connected via NX Client.

I have difficulty imagining any other cause or conclusion. I appreciate you and your time considering how to resolve this issue.