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New Member

Unable to telnet on port 143 on the public ip of the server

I have a mail server behind a firewall ( ASA 8.3 ), and I have made the configuration in order to telnet on port 143 ( natting and access rule ), but when I try to telnet to the server from the inside ( telnet on the private ip ) I get the following response : OK the Microsoft Exchange IMAP4 service is ready. But when I try it from the outside ( telnet on the public ip ) the port seemes to be opened but I get a blank screen without the message. I have removed the inspection also but nothing happened.

Please I need your help.

  • Firewalling

Unable to telnet on port 143 on the public ip of the server

Hello Osama,

Can you post the nat configuration and the ACL configuration for this setup?

Also provide the following?

packet-tracer input outside tcp x.x.x.x (host on the outside) 1025 x.x.x.x( public ip address of the server) 143

Then I would like to create some captures, but first let work on this!



Looking for some Networking Assistance? Contact me directly at I will fix your problem ASAP. Cheers, Julio Carvajal Segura
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