Alert email is sent through your own SMTP server, from your own domain. xScaler does not relay it, so your deliverability, spam filtering and rate limits stay yours.
What you need
An SMTP server that accepts mail from the internet, and a set of credentials for it. Any transactional mail provider works: Amazon SES, SendGrid, Postmark, Mailgun, or your own Postfix.
Create a dedicated sending user rather than reusing a person's mailbox credentials.
Create the contact point
Insights → Alerting → Contact points → New contact point, type Email.
| Field | Notes |
|---|---|
| Addresses | Recipients, comma-separated: [email protected], [email protected] |
| SMTP host | Your mail server, for example email-smtp.eu-west-1.amazonaws.com |
| SMTP port | 587 for STARTTLS, 465 for implicit TLS, 25 for an unauthenticated relay |
| From address | The envelope sender. Use an address on a domain you control |
| SMTP username | Leave blank for an unauthenticated relay |
| SMTP password | Required when a username is set |
| Send a single email to all recipients | One message addressed to everyone, instead of one message each |
| Subject | Optional. Takes a template |
| Message body | Optional. Takes a template |
Then Test.
Provider settings
| Provider | Host | Port | Username |
|---|---|---|---|
| Amazon SES | email-smtp.<region>.amazonaws.com | 587 | The SMTP credential, which differs from your AWS access key |
| SendGrid | smtp.sendgrid.net | 587 | apikey, literally |
| Postmark | smtp.postmarkapp.com | 587 | Your server API token, as both username and password |
| Mailgun | smtp.mailgun.org | 587 | postmaster@<your-domain> |
Whichever you use, verify the sending domain with the provider first. An
unverified From address is the most common cause of alert email that leaves
xScaler and never arrives.
Deliverability
Alert mail is transactional and bursty, which is exactly the shape spam filters dislike.
- Set SPF and DKIM on the sending domain.
- Send from a subdomain such as
alerts.acme.io, so an alerting burst cannot affect your main domain's reputation. - Group alerts so an incident is one message rather than forty. See Notification policies.
- Check your provider's rate limit against your busiest incident.
Common failures
| Delivery attempt says | Cause |
|---|---|
535, authentication failed | Wrong username or password. SES and Postmark both use credentials that differ from the ones you log in with |
530 must issue a STARTTLS command | Port mismatch. Try 587 |
connection refused, timeout | The host or port is wrong, or the server does not accept connections from the internet |
550 not authorized, rejected | The From address or its domain is not verified with the provider |
| A private or internal address | The SMTP host resolves to a private, loopback or metadata address. Delivery there is refused |
re-enter the contact point secrets | The save changed the SMTP host and left the password untouched. Re-enter it |
| Sent, nothing received | Your mail server's logs are next. The message left xScaler |
Changing the SMTP host later
The stored password is bound to the host it was saved against. Change the host and you have to re-enter the password in the same save. See Contact points.