<html><head></head><body><div style="font-family: Verdana;font-size: 12.0px;"><div>Dear Mahai,</div>
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<div>Many thanks for your response. I can ssh localhost from the server no problems. Indeed, all services on localhost are trsuted. Having investigated further, I can see that it uses the public IP address when attempting to bind to localhost rather than 127.0.0.1 when firewalld is running. Cf. <span style="line-height: 1.6em;">with firewalld running, the logs contain</span></div>
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<div>Info: Agent running with pid '204654'.<br/>
Session: Starting session at 'Wed Aug 5 14:57:49 2015'.<br/>
Info: Proxy running in server mode with pid '204654'.<br/>
Info: Waiting for connection from 'localhost' on port '30011'.<br/>
Warning: Refusing connection from '131.***.***.100'.<br/>
100' on port '30011',</div>
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<div>and I'm unable to connect, but after stopping the firewalld service, and reconnecting, they contain</div>
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<div>Info: Agent running with pid '214487'.<br/>
Session: Starting session at 'Wed Aug 5 15:19:53 2015'.<br/>
Info: Proxy running in server mode with pid '214487'.<br/>
Info: Waiting for connection from 'localhost' on port '30011'.<br/>
Info: Accepted connection from '127.0.0.1'.<br/>
Info: Connection with remote proxy completed.</div>
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<div>and I can connect no problem. The routing table is the same in both cases. My /etc/hosts file contains the localhost line first and the public hostname/IP address line second. Perhaps this is more of a firewalld question, but any further light which can be shed on the issue would be most useful.</div>
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<div>Many thanks,</div>
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<div>Will.</div>
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<div name="quote" style="margin:10px 5px 5px 10px; padding: 10px 0 10px 10px; border-left:2px solid #C3D9E5; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">
<div style="margin:0 0 10px 0;"><b>Sent:</b> Wednesday, August 05, 2015 at 5:10 PM<br/>
<b>From:</b> "Mihai Moldovan" <ionic@ionic.de><br/>
<b>To:</b> "Will Smith" <_will_@mail.com>, x2go-user@lists.x2go.org<br/>
<b>Subject:</b> Re: [X2Go-User] Problem connecting to Centos 7 (x2go 4.0.1.19).</div>
<div name="quoted-content">On 05.08.2015 03:30 PM, Will Smith wrote:<br/>
> Dear All,<br/>
><br/>
> I'm having a stange problem when attemping to connect to my Centos server using<br/>
> x2goclients (Ubuntu & mac, 4.0.5.0). I'm running firewalld, but port 22 is<br/>
> unblocked and I am able to ssh into the machine and forward X traffic. When<br/>
> accessing from both a mac and an ubuntu client the session appears to start, but<br/>
> then immediately disconnects. The client logs say:<br/>
><br/>
> Info: Proxy running in client mode with pid '12054'.<br/>
> Session: Starting session at 'Wed Aug 5 12:38:47 2015'.<br/>
> Info: Using abstract X11 socket in kernel namespace for accessing DISPLAY=:0.<br/>
> Info: Connecting to remote host 'localhost:31003'.<br/>
> Info: Connection to remote proxy 'localhost:31003' established.<br/>
> Error: The remote NX proxy closed the connection.<br/>
> Error: Failure negotiating the session in stage '7'.<br/>
> Error: Wrong version or invalid session authentication cookie.<br/>
> Session: Terminating session at 'Wed Aug 5 12:38:53 2015'.<br/>
> Session: Session terminated at 'Wed Aug 5 12:38:53 2015'.<br/>
><br/>
><br/>
> If I attempt to reconnect, I can see the session, but am unable to resume it.<br/>
> The strange thing is that if I stop firewalld, I'm able to access the server<br/>
> from both clients with no issues, which implies it's a firewall issue, but as I<br/>
> say port 22 is unblocked and I can forward X traffic. Is there some other<br/>
> obvious firewall setting I've failed do? Any assistance in fixing or diagnosing<br/>
> this issue would be highly appreciated.<br/>
<br/>
X2Go makes extensive use of SSH tunnels. I suspect your firewall is too strict<br/>
and denies access from localhost to localhost. Please make sure that locally,<br/>
all connections are allowed.<br/>
<br/>
<br/>
<br/>
Mihai<br/>
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