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Old 06-17-2006, 03:40 PM   #1
tliggins
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Registered: May 2006
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Distribution: Fedora/Cent OS/Ubuntu
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Unhappy Client / Server program cannot establish socket connection


I am new to this so please bear with me. We have setup a Cent OS server with one Cent OS client and one Red Had Fedora Core 4 client. While I can ssh and sftp from either client to the server, an application I have been give to maintain, (radmind) cannot establish communications (sockets) between the server side and client side software. I have down loaded test software, server daemon and client piece, that establishes a connection via sockets and it does not work. The error from one app is "Connection Failed" and the other (test app) gives me "file or directory not found". The test app prints "server waiting" in the term window on the server and the client can never communicate with it. Firewalls have been turned off, default sockets for the program have been opened, when the firewall was up. TCP/IP in use, no DHCP all IPs are static. Any comments on things to check and configure will be appreciated.

If additional info is needed, and I am certain it will be, I will do my best to provide ASAP.
Thanks
TL
 
Old 06-17-2006, 06:03 PM   #2
fedora4002
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Run a tcpdump or ethereal on the server side when the client is connecting to the server. If the packets from the client to the server are observed and TCP connection is established. It shows that TCP is working fine and you can check your program. If TCP connection fails, it must be something related with either firewall or network set.
 
Old 06-19-2006, 11:51 AM   #3
tliggins
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Quote:
Originally Posted by fedora4002
Run a tcpdump or ethereal on the server side when the client is connecting to the server. If the packets from the client to the server are observed and TCP connection is established. It shows that TCP is working fine and you can check your program. If TCP connection fails, it must be something related with either firewall or network set.

After running tcpdump at the server here is the output. Note that the number of user data bytes in the datagram is 0. I am now looking into exactly what this means or what would cause this to be 0.
Thanks for your help.

10:09:59.912154 IP n82tl08.57991 > n82pb10.6662: S 4207152429:4207152429(0) win 5840 <mss 1460,sackOK,timestamp 427605300 0,nop,wscale 2>
10:09:59.912239 IP n82pb10.6662 > n82tl08.57991: S 2041000031:2041000031(0) ack 4207152430 win 5792 <mss 1460,sackOK,timestamp 242044934 427605300,nop,wscale 2>
10:09:59.912465 IP n82tl08.57991 > n82pb10.6662: . ack 1 win 1460 <nop,nop,timestamp 427605301 242044934>
10:10:59.899097 IP n82tl08.57991 > n82pb10.6662: F 1:1(0) ack 1 win 1460 <nop,nop,timestamp 427665301 242044934>
10:10:59.899256 IP n82pb10.6662 > n82tl08.57991: . ack 2 win 1448 <nop,nop,timestamp 242104931 427665301>
 
  


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