mailrelay

mailrelay is a simple mail relay that can take unauthenticated SMTP emails (e.g. over port 25) and relay them to authenticated, TLS-enabled SMTP servers. Plus it's easy to configure.

Use case

Some older appliances such as scanners, multi-function printers, RAID cards or NAS boxes with monitoring, can only send email without any authentication or encryption over port 25. mailrelay can send those emails to your Gmail, Fastmail or other provider.

Run mailrelay on a local PC and set your device (e.g. scanner) to send mail to that PC.

mailrelay is written in Go, and can be compiled for any Go supported platform including Linux, MacOS, Windows.

Example (Linux)

On local PC (192.168.1.54) create file /etc/mailrelay.json with contents:

/etc/mailrelay.json

{
    "smtp_server":   "smtp.fastmail.com",
    "smtp_port":     465,
    "smtp_username": "username@fastmail.com",
    "smtp_password": "secretAppPassword",
    "local_listen_ip": "0.0.0.0",
    "local_listen_port": 2525
}

Run mailrelay,

./mailrelay

Default location for configuration file is /etc/mailrelay.json but can be changed via --config flag. For example,

mailrelay --config=/home/myname/mailrelay.json

Configure your scanner or other device to send SMTP mail to server 192.168.1.54:2525. Each email will be relayed to smtp.fastmail.com using the credentials above, including any file attachments.

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mailrelay

Use case

Example (Linux)

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