UNIX for Dummies Questions & Answers

Hi all,

I would like to know if I can send unix mail to 'external email addresses'.

My unix server is leo@ABCcompany.com.

I am able to send emails to firstname.lastname@ABCcompany.com.

But, we have some email addresses in our team on our parent company's server - ex: firstname.lastname@ParentCompany.com. The emails to these folks are not going through.

I was wondering two things 1) can we send emails to external addresses? 2) If so, do you think I have to contact my network adminstrator so that he can change the permissions/settings so that I could send emails externally.

I have also tried sending a test email to my personal account on @yahoo.com and that email did not go through.

Please help. Thank you in advance.

To connect local mail to the outside internet, you'll need a Mail Transfer Agent like sendmail.

In general you should be able to send a message to any server that accepts the incoming connection. You can see that it's working for local servers. Configuration issues at either server or in between can prevent the successful delivery of your message.

For example, if your unix server isn't in DNS and the ParentCompany server will only accept e-mail from DNS resolvable systems, your incoming connection will not be accepted.

Many viruses set up a mini smtp server on the Windows workstation which churns out spam/virus e-mails. I've configured our network to refuse to allow port 25 connections from any workstation not specifically configured as a mail transfer agent.

You can test these by attempting a connection manually

Code:

$ telnet parentcompany.com 25

If you don't get anything (generally a banner of some sort is displayed), you're probably being blocked at your local company firewall. If you get a banner, you can try to build a session and see what happens:

Code:

$ telnet parentcompany.com 25
220 mail.parentcompany.com ESMTP Postfix
HELO abccompany.com
250 Hello abccompany.com
MAIL FROM: <joy.k@abccompany.com>
250 Ok
RCPT TO: <my.friend@parentcompany.com>
250 Ok
DATA
354 End data with <CR><LF>.<CR><LF>
Subject: Example Message
From: joy.k@abccompany.com
To: my.friend@parentcompany.com

Yo,

Sending a test message.

  Later,
Joy
.
250 Ok: queued as 45334
QUIT
221 Bye

The lines that begin with numbers are server responses. The other lines are what you're typing.

You should get either something like the above session, or you might receive an error.

In both of these situations, the best way to resolve this is to configure your server to route e-mail through your local MTA and let it deliver e-mail. You'll have to check your e-mail server's configuration to see what the options are to make this setting.

Carl