This question has been asked a thousand times; but, not with this flavor. I am going to mention a few "programming" things, but I am only interested in the network issues.
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In the past, I've installed Internet services as daemons and as xinetd.d with no problems. Those approaches do not meet my needs. And, perhaps, nothing will.
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- the service was converted from VB-6 to wxPython. It has a GUI which is accessed with either "remote desktop" or VNC.
- the wxPython service works on Windows and can be accessed from other hosts on my LAN
- the wxPython service works on CentOS and Fedora, but can only be accessed from within the server host. Even from other user-ids. But, I cannot get to it from other hosts.
- ipchains AKA firewall ports are marked for INPUT.
- The server host uses autologin to fire up a useid in group "user". I do not want it running as "root". the .bash_profile fires the service up.
- the service is heavily mult-threaded, and supports devices connected to serial ports asynchronously with the ephemeral port threads (all this works).
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There are some programming solutions that I would rather not develop.
- a proxy service that runs under xinetd.d.
- separate the GUI code from the Internet and serial port code. Allocate a "control" port for remote GUI control. a'la SAMBA & SWAT
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Is there any hope, that I can run it as is, by doing some network configuration stuff.
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Thanks in advance

Hi -

Sorry ... but I can't make any sense out of what your trying to ask.

Q: What "goal" are you trying to achieve
<= Never mind the "how's" - exactly WHAT do you want to accomplish?

Q: What platform(s) are you using?
For example, do you want to have a Windows "client" remotely log in with a GUI to a Linux "server"?

Q: Any other important details/constraints?

Again: please focus exclusively on your REQUIREMENTS (the "what"), do *not* worry about "implementation" ("how") yet.

Thanx in advance .. PSM

PS:
If I'm understanding you even 1/2 way correctly, perhaps this link might be useful to you:

http://www.ltsp.org/

PPS:
This beast started out in life as a VB6 app??? Omg omg omg...

The 2002 project specification is 15 pages long accompanied by a 10 page Principles of Operation. I'm sure you don't want that.
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To keep things as brief as possible, please assume:
service: a program using socket "bind" & "accept" methods. As in - services run on servers. Call this program SERV
client: a program using socket "connect" method. Call this program USER
SERV and USER are using a proprietary full-duplex Internet protocol CPUXA/IP that I developed in 2002 and have been using ever since
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requirements:
1) SERV and USER shall be PC platform agnostic (Linux, MAC, and Windows)
2) SERV shall not have root privileges
3) SERV has a monitoring and control GUI, which shall be remotely accessible by VNC, remote desktop, or equivalent - in conjunction with it's support of at least 9 instances of USER.
4) USER shall be able to run on any host on the LAN without getting a connection refused - excepting the 9 instance limit.
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What does work:
SERV on Windows, USER on Windows
SERV on Windows, USER on FC-13 or CentOS
SERV on CentOS 192.168.4.5, USER on Centos 192.168.4.5
SERV on FC-13 192.168.4.14, USER on FC-13 192.168.4.14
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I am a retired systems programmer with 50+ years of experience (mostly in IBM assembler) developing interrupt handlers, communications protocols, and run-time libraries for compilers.

This thing started out in "C" (see Mark A. Day's XALIB) but the community I was working with did not understand "C". VB-6 was the community's 2002 choice. It is the only VB-6 thing I've ever written. I am pretty much language agnostic. Python is my current favorite, but LUA and TCL are close seconds. I hate C++ and am terrible at user interfaces. I use wxGlade to hammer out the appearance.

OK - I confess, I still don't understand. But I think this might be the central problem you're trying to solve:
In other words, is "the problem" that you simply can't establish a connection from ANY remote clients if you have a Linux (either CentOS or Fedora). Correct?

Suggestions:
1. Can you establish ANY kind of remote connections from one Linux host to the other?
For example, can you "telnet", "ftp", or "ssh" between hosts?

2. If you have a firewall, disable it (if only for debugging). Get it working any way you can first. If a firewall is the culprit, we can figure out appropriate filters later.

3. If you have SELinux active, disable it (if only for debugging).

4. Wireshark can be an extremely helpful troubleshooting tool:
http://wiki.wireshark.org/NetworkTroubleshooting

5. NMap is an equally useful troubleshooting tool:
http://www.linuxhomenetworking.com/w...roubleshooting

http://nmap.org/bennieston-tutorial/

'Hope that helps .. PSM

bvn -

Any luck resolving this problem?

Inquiring minds would like to know

Thanx in advance .. PSM

Will try the aforementioned tools and get back.
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Yes, The only failing configuration is when SERV is running on one of the aforementioned Linux distro's.
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The FTP, Telnet, VNC, NFS, caching DNS, NTP, and Samba services on the "failing" server work just fine. Only SERV is not remotely accessible, even though it has successfully bound to the server host.
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The only difference between the working services and mine (given my limited knowledge of Linux) is that they are initiated (launched, activated, assigned a PID, etc.) by Linux system internals and SERV isn't. It is initiated manually, via VNC, or Remote Desktop, in an unprivileged user account. I intend to automate SERV's initiation after things stabilize.
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I have already tried turning off SELinux and the firewall before asking for help. I try to do my homework before asking - which doesn't mean that I am never guilty of stupid errors :-)
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I've been designing and implementing IP protocols for almost 20 years - just never on Linux. My earliest attempt was 2780-RJE (well known port #5). The original 2780-RJE was BiSynch. IPCHAINS seem quite straight forward, not to mention, a vast improvement over some of the stuff I've had to deal with, back in the day.

still working on situation.
Thanks for the tool recommendations. "nmap" especially.
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Lost my Linux home server box to a client with a dead machine last weekend. Just built a new one and installed it in my wiring closet. I am loading my Python server software onto it, as I write this.

Figured it out - thanks to your most welcome help.
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nmap was the ideal tool. When "nmap 127.0.0.1" showed my port as being open, everything became clear.
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- my first error was using a port number < 1024 on Linux. Apparently, that range is reserved for the root privileges.
- my second error was programmatic. On Linux, the gethostbyname() was getting me to 127.0.0.1 (unlike Windows).
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I suppose these errors (false assumptions?) are well known to the Linux community. Now, I know them too. Many thanks.

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