topic Re: problem while opening a client socket in Operating System - HP-UX

problem while opening a client socket

kumasudh — Thu, 07 Aug 2008 05:19:33 GMT

Hi All,

I am facing one strange issue with my application running on HP-UX 11iv3.It tries to open a client socket with a service running at port 6670.

#netstat -an |grep 6670
tcp 0 0 *.6670 *.* LISTEN

#telnet 127.0.0.1 6670
Trying...
Connected to 127.0.0.1.
Escape character is '^]'.

the service rejects the client's connect request with errno 239(connection refused) .

Could somebody help me here to figure out why the service is refusing connect request .

Thanks,
Best Regards
Sudhir

Re: problem while opening a client socket

Torsten. — Thu, 07 Aug 2008 05:49:43 GMT

First I would try to find out "who" is listening on that port - use "lsof".

Re: problem while opening a client socket

Ralph Grothe — Thu, 07 Aug 2008 06:55:33 GMT

Maybe the server is configured to only allow connects from certain source addresses, or some tcp wrapper is in effect.
As Torsten said you should identify the server by e.g.
# lsof -nPi tcp:6670 | awk '/LISTEN/{print$2}'|xargs ps -fp

Re: problem while opening a client socket

kumasudh — Thu, 07 Aug 2008 07:03:37 GMT

Hi,

Here is the output..

#/usr/local/bin/lsof -nPi tcp:6670 | awk '/LISTEN/{print$2}'|xargs ps -fp
UID PID PPID C STIME TTY TIME COMMAND
smsdba 4520 4519 0 13:22:14 pts/tb 0:00 /opt/OC/lbin/ftc_mibproxy -MibService ha_ftcmib -FtcService ha_ftchb

the service "ha_ftcmib" is supposed to listen on 6670(configured in /etc/services) .

#/usr/local/bin/lsof |grep ha_ftc
ftc 4519 smsdba 4u IPv4 0x115b119400 0t0 TCP *:ha_ftc (LISTEN)
ftc 4519 smsdba 6u IPv4 0x115b5fc680 0t0 TCP *:ha_ftchb (LISTEN)
ftc 4519 smsdba 7u IPv4 0x115b2b0d00 0t0 TCP *:ha_ftchboam (LISTEN)
ftc 4519 smsdba 8u IPv4 0x1159c66c80 0t0 TCP localhost:ha_ftchb->localhost:49635 (ESTABLISHED)
ftc 4519 smsdba 9u IPv4 0x1159c66080 0t0 TCP localhost:ha_ftchb->localhost:49636 (ESTABLISHED)
ftc_mibpr 4520 smsdba 3u IPv4 0x115ad78680 0t0 TCP localhost:49635->localhost:ha_ftchb (ESTABLISHED)
ftc_mibpr 4520 smsdba 4u IPv4 0x115b36f980 0t0 TCP *:ha_ftcmib (LISTEN)
ftc_mibpr 4520 smsdba 5u IPv4 0x1159c66380 0t0 TCP localhost:49636->localhost:ha_ftchb (ESTABLISHED)

Thanks,
Best Regards
Sudhir

Re: problem while opening a client socket

Fabio Ettore — Thu, 07 Aug 2008 07:16:58 GMT

Hi,

are youy experiencing problems with that service on that port? Or are you complaining that just why telnet on port 6670 is refusing connections in that way?

Have you other systems configured with that service listening on port 6670? If so have you the same behaviour on those ones?

Best regards,
Fabio

Re: problem while opening a client socket

Deepak Kr — Thu, 07 Aug 2008 11:58:07 GMT

Hi,

clear the port using lsof and try connecting
check

#netstat -an |grep 6670

It is not neccessary that port is also available for telnet....

Re: problem while opening a client socket

Ralph Grothe — Thu, 07 Aug 2008 12:11:20 GMT

Also it can be heavily dependent on the application protocol spoken.
There are servers where the server side initiates the communication (I think SSH is such a candidate), and loads of other which wait for the client to pass the proper cue first.