Connection Timeout on aws when Telnet on Port 25 [closed]

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Thanks you for your time.

I have just set up a Postfix mail server which is running as MTA in one of my aws instances. I can successfully connect to the localhost through 'telnet localhost 25', and I can send emails to both external and internal email accounts when connected on localhost, however whenever I try to connect through 'telnet zwitch.it 25' or 'telnet mail.zwitch.it 25' I get a connection timeout.

I have set up all my records, including the MX record and the SPF record with the values "v=spf1 include:amazonses.com include:zwitch.it -all" and "spf2.0/pra include:amazonses.com include:zwitch.it ~all".

I really cannot find what is the problem here, if there is a firewall, or if the port is blocked, or maybe something is wrong with my postfix configuration... I would really appreciate if you could help me.

To set up my postfix mail server I followed the instructions at http://flurdy.com/docs/postfix/ where it mentions the installation of a simple postfix server.

I thank you in advance for the help.

EDIT: Thanks to the answer below the problem was fixed. I only had to go on my aws security groups and add SMTP to the list!

Answer 1

It's one of three things:

1.) You need to edit your security group in AWS to allow port 25 from all external IP addresses.

2.) Your DNS entries for mail.zwitch.it do not point to the external IP address of the AWS instance.

3.) You don't have a static IP (elastic) address configured for the instance.