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I've had a problem sending mail on my server. My host has informed me that it is due to not sending it through their relay. They tried to tell me what to do, here are their instructions:

Edit /etc/mail/sendmail.cf or /etc/sendmail.cf depend on your operating system.

and edit as 

# “Smart” relay host (may be null)


Neither file exists for me, and they're taking forever to respond. I was hoping someone else here might know a solution.

I'm running CentOS5.5 with cPanel/WHM on a VPS

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1 Answer 1

There might be a specific way to do it in cpanel, but provide a general answer for Exim, you need to create a new router that matches all non-local mail. There's already one in the default exim config file called "dnslookup". That router routes all non-local mail to a transport called "remote_smtp" that uses DNS to decide what server to send the mail to.

So, to add a static route to an outbound mail server, add a new router above the existing dnslookup router (because order matters in routers, your mail will be handled by the first one that matches).

Here's an example that, in a simple config (one outbound server only, on port 25, no authentication) should Just Work:

  driver = manualroute
  domains = ! +local_domains
  route_list = * <mailserver_hostname>
  transport = remote_smtp

Here's a slightly more complex example from my own config using pobox.com as a relay, on port 587, using authentication:

# This goes in ROUTERS section
  driver = manualroute
  domains = ! +local_domains
  route_list = * sasl.smtp.pobox.com::587
  transport = auth_remote_smtp

# This goes in TRANSPORTS section
  driver = smtp
  hosts_require_auth = *

# This goes in AUTHENICATORS section
  driver = plaintext
  public_name = plain

(pobox only support LOGIN and PLAIN for auth types, but it supports TLS which Exim will use out of the box, so my creds only go over a TLS link).

Here's a log example of mail I sent outbound on that server using the configs above:

2010-11-26 10:04:49 LCHZ81-0000HN-NN <= SENDERADDRESS H=localhost (g3) [] P=esmtp S=441  
2010-11-26 10:04:50 LCHZ81-0000HN-NN => RECIPADDRESS R=static T=auth_remote_smtp H=sasl.smtp.pobox.com [] X=TLSv1:DHE-RSA-AES256-SHA:256  
2010-11-26 10:04:50 LCHZ81-0000HN-NN Completed  
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