Q/R issue between Orthancs (RHEL 8 <--> Ubuntu)

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1

Hello,

Thank you so much for the Orthanc project. I have an issue and I am not able to resolve it.

I have two systems. One consists Orthanc on RHEL and the other consists Orthanc on ubuntu. I am trying to achieve Q/R between them.

When I try to to establish a connection by entering the right IP addresses and the correct port numbers, I can only C-ECHO from the RHEL Orthanc to the Ubuntu Orthanc and not the other way around. I believe since the connection is not established, we can’t even attempt a Q/R.

After digging deeper I found that you asked to use the commands in this link to open up the ports in RHEL.

https://book.orthanc-server.com/faq/redhat.html

After trying this also, things didn’t work.

I continued to try to understand why the connections could not be working and found something interesting after running a few commands.

I ran the following command on RHEL:

sudo ss --tcp --listen --numeric --processes | grep Orthanc

and got the output as the following:

State Recv-Q Send-Q Local Address:Port Peer Address:Port Process

LISTEN 0 50 0.0.0.0:4242 0.0.0.0:* users:((“Orthanc”,pid=104419,fd=7))
LISTEN 0 128 0.0.0.0:8042 0.0.0.0:* users:((“Orthanc”,pid=104419,fd=8))

similarly I ran the same on the Orthanc on ubuntu as well and I got the following:

State Recv-Q Send-Q Local Address:Port Peer Address:Port Process

LISTEN 0 128 *:8042 : users:((“Orthanc”,pid=3876,fd=9))
LISTEN 0 50 *:4242 : users:((“Orthanc”,pid=3876,fd=8))

I can see some differences in the addresses for local and peer. I am less aware about networks but from what I read, I believe that the TCP networks for the RHEL could be blocked/inactive?

If so what can I do? Or can I transfer in any other way?

Please let me know if you require any-other information.

2

So I continued to work on it and I found something interesting again. I tried to install orthanc via docker and in that case,

And in that case when I run the command:

sudo docker run -p 4242:4242 -p 8042:8042 –rm -v /tmp/orthanc.json:/etc/orthanc/orthanc.json:ro jodogne/orthanc-plugins

The opposite effect takes place, which means I can send C-ECHO to the orthanc in RHEL from the Orthanc in Ubuntu.

I also ran the sudo ss --tcp --listen --numeric --processes

And I get:

State Recv-Q Send-Q Local Address:Port Peer Address:Port Process

LISTEN 0 128 *:4242 : users:((“docker-proxy”,pid=109115,fd=4))
LISTEN 0 128 *:8042 : users:((“docker-proxy”,pid=109102,fd=4))

As you can see a star exists for this but the process is a docker-proxy.

And when I run:

sudo docker run -p 4242:4242 -p 8042:8042 --network=host --rm -v /tmp/orthanc.json:/etc/orthanc/orthanc.json:ro jodogne/orthanc-plugins

I can only C-ECHO from the RHEL Orthanc to the Ubuntu Orthanc and not the other way around. (So the effect that happens my first email)

3

Hello,

This looks like a network configuration issue that is independent from Orthanc.

I would highly suggest you to first learn how to connect two Orthanc servers for query/retrieve (DICOM C-MOVE) on the same computer:
https://book.orthanc-server.com/dicom-guide.html#dicom-network-protocol

Once you have this running, try to understand your network configuration issue, which is most probably linked either to some firewall (iptables), or to a misunderstanding about how DICOM query/retrieve works. Indeed, pay attention to the fact that for query/retrieve to work, the “client” (SCU) must be able to contact the “server” (SCP), but that the reverse must also be true: The “server” (SCP) must be able to contact the “client” (SCU). This is how DICOM networking works (check out the REST API or DICOM C-Get for alternatives).

Regards,
Sébastien-

4

Hello Sebastien:

Thank you for your reply. You are right, it was a firewall issue, that we could resolve. And it works now.

Thanks!

Warm regards,
Rachit Saluja