[cs615asa] hw4 security groups

[Jan Schaumann]

Javed Akhtar <jakhtar at stevens.edu> wrote:
 
> telnet nexus.stevens.edu 25

Make sure you have the right server.  In your homework submission, make
sure to write down how you derived at the conclusion to choose
'nexus.stevens.edu', and think about whether an external mail server
trying to send mail would come to the same conclusion.

> Then, I changed the port to 587 since Steven's mail server works on port 587
> as stated in ITWIKI page. But that also didn't work. Below I am mentioning
> all what I tried.
> 
> telnet nexus.stevens.edu 587
> Trying 155.246.14.12...
> Connected to nexus.stevens.edu.

You are now connected, so all is working from a TCP/IP point of view
here.

> Escape character is '^]'.
> 220 nexus.stevens.edu ESMTP Postfix
> mail from: jakhtar at stevens.edu
> 250 2.1.0 Ok
> rcpt to: jakhtar at stevens.edu
> 554 5.7.1 <ec2-50-17-124-180.compute-1.amazonaws.com[50.17.124.180]>: Client
> host rejected: Access denied

Think about what this might mean.  Look up what an SMTP error code 554
indicates.

-Jan