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Old 01-17-2013, 02:43 AM   #1
sudeepnarayan.banerjee
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Need to open telnet port


Hi All,

I hav a 3 machines running oracle RHEL5-5.8(64bit) with ip 10.1.1.1, 10.1.1.2, 10.1.1.3.
ping & ssh to these servers are fine. Now, when i try to do telnet i get Unable to login message.
[root@sysman ~]# telnet 10.1.1.2 8002
Trying 10.1.1.2...
telnet: connect to address 10.1.1.2: Connection refused
telnet: Unable to connect to remote host: Connection refused

[root@sysman ~]# telnet 10.1.1.3 8002
Trying 10.1.1.3...
telnet: connect to address 10.1.1.3: Connection refused
telnet: Unable to connect to remote host: Connection refused

Same thing happens from each other server as well. I have made disable=no in /etc/xinetd.d/ekrb5-telnet & restarted xinetd service. Also added a rule in iptables: iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 8002 -j ACCEPT
and saved-restarted iptables service.

Still does not work.

[root@sysman ~]# cat /etc/services | grep 8002
teradataordbms 8002/tcp # Teradata ORDBMS
teradataordbms 8002/udp # Teradata ORDBMS

[root@sysman ~]# netstat -anp | grep 8002
tcp 0 0 0.0.0.0:8002 0.0.0.0:* LISTEN 5015/httpd
tcp 0 0 10.1.1.2:8002 10.2.132.21:26947 TIME_WAIT -
tcp 0 0 10.1.1.2:8002 10.2.132.21:27076 TIME_WAIT -
tcp 0 0 10.1.1.2:8002 10.2.132.22:37954 TIME_WAIT -
tcp 0 0 10.1.1.2:8002 10.2.132.22:38038 TIME_WAIT -
tcp 0 0 10.4.132.11:8002 10.2.132.21:27027 TIME_WAIT -

Can anyone please help!

Thanks in advance
Sudeep
 
Old 01-17-2013, 03:06 AM   #2
acid_kewpie
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This is NOT the "telnet port". You really need to understand that here telnet is being misued as a simple testing tool. you are NOT technically using telnet as a service in any way.

There is nothing listening on those ports, there is nothing to "open". You need to actually run something that wants to accept connections.
 
Old 01-17-2013, 04:16 AM   #3
sudeepnarayan.banerjee
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Hi Chris,

Thanks for the response! Well yes, 8002 port is not being used or telnet service. When I do telnet 0 25; it works fine. But is the NLB(Network Load Balancer Team) who wants to have this port configured for doing telnet.
But after opening in iptables and making disable=no in telnet file, the needful is not met.

Could you please tell me what exactly needs to be run to make things work here and accept connections? Please note that I cannot download(yum/rpm/apt-get) etc in these servers.

Thanks in advance
Sudeep

Last edited by sudeepnarayan.banerjee; 01-17-2013 at 04:18 AM.
 
Old 01-17-2013, 04:38 AM   #4
acid_kewpie
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something needs to run on that port. I don't know what that is. You tell me. what is that port for?
 
Old 01-17-2013, 04:50 AM   #5
sudeepnarayan.banerjee
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Hi Chris,

It is for Load Balancer to route connections between physical servers and port 8002. The default port is 23 for uncryoted telnet communications and 8002 happens to be related "Cisco Systems Unified Call Manager Intercluster"

Also do not know what needs to be done at the port level, apart from iptables etc. please help!

Thanks in advance
Sudeep
 
Old 01-17-2013, 05:01 AM   #6
acid_kewpie
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what has port 23 got to do with anything? Why did you mention it? you are NOT asking about telnet, again it's just a simple test trick that people use. This is NOT about telnet.

Why did you mention Cisco UCM? Is that what you're trying to use? Or just something you found after googling for info about port 8002?

Ahh, OK, you DO have httpd listening on 8002, sorry I didn't see that in the netstat originally.

So you did an "iptables -A", tagging the permit onto the end of the rulebase. Maybe there's a drop rule already above it. Show us the output of "iptables -vnL" please. Also try conencting to 127.0.0.1:8002 on the box itself. you would probably have more clarity if you use curl instead of telnet - "curl -v 127.0.0.1:8002"

Last edited by acid_kewpie; 01-17-2013 at 05:05 AM.
 
Old 01-17-2013, 05:06 AM   #7
sudeepnarayan.banerjee
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Hi Chris,

yes you are correct. I mentioned meaning of 23 port just to say that here telnet has to be used in 8002.

Yes I captured UCM from wiki about 8002.

So, what needs to be done next?

Now, I restarted xinetd service, it says,

[root@sysman ~]# telnet 10.1.1.2 8002
Trying 10.1.1.2...
Connected to sysman.sysworld.local (10.1.1.2).
Escape character is '^]'.
Connection closed by foreign host.

Is this ok, you say?

Thanks in advance
Sudeep
 
Old 01-17-2013, 05:11 AM   #8
acid_kewpie
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that's working.
 
Old 01-17-2013, 05:29 AM   #9
sudeepnarayan.banerjee
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Thanks a lot!

Sudeep
 
  


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