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

osama.sisan
Level 1
Level 1

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.

1 Reply 1

Julio Carvajal
VIP Alumni
VIP Alumni

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!

Regards,

Julio

Julio Carvajal
Senior Network Security and Core Specialist
CCIE #42930, 2xCCNP, JNCIP-SEC
Review Cisco Networking for a $25 gift card