Configuring Exim to use MxGuard as a smarthost

Exim can route all non-local mail through the MxGuard smarthost with a dedicated router and an authenticated smtp transport.

Router (before your dnslookup router):

send_via_mxguard:
  driver = manualroute
  domains = ! +local_domains
  transport = mxguard_smtp
  route_list = * smtp.mxguard.uk::587

Transport:

mxguard_smtp:
  driver = smtp
  hosts_require_auth = smtp.mxguard.uk
  hosts_require_tls = smtp.mxguard.uk

Authenticator (plain SASL):

mxguard_login:
  driver = plaintext
  public_name = LOGIN
  client_send = : your-generated-username : your-generated-password

Reload Exim, then add include:_spf.mxguard.uk to your SPF record. Send a test and check the dashboard's outbound log to confirm acceptance. On some builds you'll prefer to store the credentials in a separate file rather than inline. For IP-allowlist mode, omit the authenticator and connect from your registered static IP on port 25.