email outside domain accounts

[David Vann_2]

sendmail has been working great for years now.  I use it to send emails to my pager via scripts that monitor the ERP package, DB, OS etc.  Now we are upgrading our exchange server to 2010.  Our exchange administrator will not create a relay connector with the IP for the hosts I'm using.

1) sendmail: Is there a way to bypass exchange server to send email to accounts outside our domain?  With sendmail I get 550 5.7.1 unable to relay, because of the lack of a relay connector.  What are my options if any?  Are there any arguments for opening the relay connector?  There concern is someone spoofing our IP address and sending emails out.

2) postfix: I've tried but I get the same message.  Is there a way to configure postfix to bypass exchange?

3) other products: Are there other products I can use to get this functionality?

[David Vann_2]

If we create a relay connector and grant access to specific IPs are there any concerns?

[David Vann_2]

Is there a way for postfix to authenticate with exchange and pass the email message out?  From what I've researched so far this will be difficult to script.  Don't you have to encode the login and password using base64? 

[Steven E. Protter]

Shalom,

Due to spam, mail servers on the public internet are running a number of new checks that might prevent delivery from an HP-UX server sitting inside a Corporate network behind a firewall.

These criteria do not apply to all but will give you a guide to what is possible.

The domain name of the email must be an IP address that can be looked up by domain name on the public Internet.

If the domain name on the system email is steve@server.yournetwork.com

server.yournetwork.com must be able to be resolved via DNS. What you actually do in this case is hack with sendmail.cf to get the domain name yuou want.

Some public email severs make sure the reverse lookup of the sending IP address (your public IP normally on your Corporate firewall) matches an IP address assigned to your domain (An A record).

Lot of DNS here.

In most Corporate environments port 25 is closed to all but the Exchange server. You might be able to work with the Exchange admin to get your emails passed through.

SEP

[Bill Hassell]

If your HP-UX server can reach the Internet directly, you have two choices for authentication. Use the sendmail authentication package for Cyrus/SASL files, OpenSSL and several pages of instructions. Or you can use the attached script. It is fairly detailed and has limited authentication choices but it has worked for a number of destinations. The attachment is named mailxauth.txt but you can drop the .txt or replace it with .sh when you save it. Lots of comments in the code.

[Bill Hassell]

Here is the SASL/Cyrus document.

[David Vann_2]

I appreciate all the responses.

We've decided to use postfix off a linux box.  We're working on authenticating postfix with exchange which isn't working very well so now we are looking to have postfix sit outside our DMZl and run as a standalone server without relaying.