forked from drew/smtprelay
22ef0c2ee6
This has several benefits: - Configuration errors are caught at startup rather than upon a connection - mailHandler() has less work to do for each connection Rather than relying on remote_user and remote_pass to control whether authentication is used, introduce an explicit "none" type for remote_auth, and make that the default. (This is effectively the same default behavior since remote_user and remote_pass default to empty.) Also, we are in a better position to more thoroughly check for configuration errors or mismatches: - If remote_auth is given, remote_user and remote_pass are required. - If remote_auth is given, remote_host is also required (because it makes no sense to say we're going to authenticate if we have no server to which to authenticate.) - If remote_user or remote_pass are given, remote_auth cannot be "none".
smtprelay
Simple Golang based SMTP relay/proxy server that accepts mail via SMTP and forwards it directly to another SMTP server.
Why another SMTP server?
Outgoing mails are usually send via SMTP to an MTA (Mail Transfer Agent) which is one of Postfix, Exim, Sendmail or OpenSMTPD on UNIX/Linux in most cases. You really don't want to setup and maintain any of those full blown kitchensinks yourself because they are complex, fragile and hard to configure.
My use case is simple. I need to send automatically generated mails from cron via msmtp/sSMTP/dma, mails from various services and network printers to GMail without giving away my GMail credentials to each device which produces mail.
Main features
- Supports SMTPS/TLS (465), STARTTLS (587) and unencrypted SMTP (25)
- Checks for sender, receiver, client IP
- Authentication support with file (LOGIN, PLAIN)
- Enforce encryption for authentication
- Forwards all mail to a smarthost (GMail, MailGun or any other SMTP server)
- Small codebase
- IPv6 support