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Telnet outbound firewall

Posted on 2012-09-21
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Last Modified: 2012-10-06
I want to send telnet requests outbound to test various services,all outbound ports on my firewall apart from 80, 443 and 53 are closed. one being mail port 25. I am wondering do I just need to open port 23 to allow telnet out or does the port I am telneting to (port 25) also need to be opened on the firewall outbound. I'm thinking its only port 23 but just needed to confirm
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Question by:Sid_F
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Expert Comment

by:Ashok Dewan
ID: 38421106
port number 23 should be open on that host where you are connecting to. And also If your firewall has restricted all ports except 80,443,25 and 53 for outgoing the you must set your firewall to allow also port 23 for outgoing request.

Thanks and regards
Neil40m
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Author Comment

by:Sid_F
ID: 38421131
You may need to re-read the question. The ports outbound were not in relation to telnet they were in relation to the port telnet is connecting to ie 25
I understand I need 23 open on the firewall for telnet but do I need 25 open as well or does it run over port 23 in some way
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Expert Comment

by:mvdeveloper
ID: 38421161
Telnet is just the protocol. It normally lives on port 23, but if you are telnetting to port 25 (why?) then that will need to be opened.
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Expert Comment

by:Ashok Dewan
ID: 38421239
port number 25(SMTP protocol) has no concern with telnet application. telnet port no. 23.
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Author Comment

by:Sid_F
ID: 38421466
Its to test connectivity to an smtp server from a command line. So do I need 23 , 25 or both?
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Accepted Solution

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Sid_F earned 0 total points
ID: 38436742
I found out I need 25 as well as 23
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Author Closing Comment

by:Sid_F
ID: 38469693
resolved
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