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Callback connections strangeness

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Pepa Kokes, User (Posts: 32)
Aug 11, 2022 10:44:44 am EDT
Support level: Free or trial
Hi! After a number of years of happy usage of RU, I tried to add a new computer to my RU family and once again encountered an issue that doesn't make any sense. I remember that I encountered that same issue years ago - and apparently it was never resolved and works the same even with the current 7.0.5.0 version.

The setup I am using is this:

1) One machine with a public IP address that runs a RU-Viewer.
2) Several machines without public IP addresses that run a RU-Host in a callback mode (let's call them X and Y).
3) The viewer listens on port 5651.
4) The hosts connect to this port. (Actually, it's a bit more complicated since I am not connecting directly but rather through a SSH tunnel, but that's not really relevant - eventually the traffic reaches port 5651 on the Viewer machine.)

However, I found that I can't get the connections to work properly if multiple hosts are alive at the same time. I would get a message saying that a connection from machine X was automatically accepted by the viewer (which is intended), but then in a few seconds later I would get another message that another connection from machine X was automatically accepted. But I would never ever see a connection from machine Y.

To fix this problem, I need to open the Remote Utilities Host Settings on both X and Y and change their listening port (Network -> Port -> Port) to different values (e.g. 5650 for X and 5651 for Y). Once I do that, I start getting messages about accepting connections from both X and Y and everything would begin to work perfectly - e.g. I can remote control each of the hosts.

But I feel this must be a bug - there's absolutely no reason why the *listen* port on the host should have *any* relevance to that host's callback connections, and in particular, why should the viewer care - but it does. I would understand if the viewer was only capable of handling one connection so the first machine would connect to the viewer's listen port and all others would get refused, but that's not the case - the viewer is perfectly happy to accept several simultaneous connections from several different hosts, provided that *their* listen port (which should not come into play *at all* during callback connections) is different for each host.

Could the developers please look into this and fix the viewer*) to not require different host ports? Thank you.

*) Probably the bug originates with the viewer - if I shutdown host X and only keep Y, it will connect to the viewer fine. The same happens if it is lucky enough to send its connection packet first.

The old topic can be found here: https://www.remoteutilities.com/support/forums/messages/forum1/message4906/1011-callback-connection-docs-need-an-update
Pauline, Support (Posts: 2886)
Aug 11, 2022 5:41:41 pm EDT
Hello Pepa,

Thank you for your message.

Could you please clarify if you mean that you use the latest version 7.1.5.0? If this is the case, could you please also confirm that all of your Hosts and Viewer are updated to the same version? Some issues might be caused by the version mismatch, so this is just in case to eliminate this factor.

Looking forward to your reply.
Pepa Kokes, User (Posts: 32)
Aug 11, 2022 11:12:42 pm EDT
Support level: Free or trial
That was my mistake. Yes, I am using version 7.1.5.0 on all machines, both as a host and as a viewer.
Pauline, Support (Posts: 2886)
Aug 12, 2022 11:31:31 am EDT
Hello Pepa,

Do you mean that your Host and Viewer were already updated to the most recent version but the issue still persists? If this is the case, then I'll forward the issue to our developers and will ask for their input on this as well to see if we will be able to fix it in our future updates.

I'll get back to you with an update on this shortly.
Pepa Kokes, User (Posts: 32)
Aug 12, 2022 11:37:02 am EDT
Support level: Free or trial
Yes, I am fully upgraded and the issue persists. In fact, it has been in existence since I first started to use RU, some six years ago.
Pauline, Support (Posts: 2886)
Aug 12, 2022 1:45:39 pm EDT
Hello Pepa,

Thank you for the clarification.

I've forwarded the issue to our devs and asked them to look into this once again.

I'll let you know as soon as there are any updates from our developers on this issue.

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